diff --git a/src/main/java/slvtwn/khu/toyouserver/application/GroupService.java b/src/main/java/slvtwn/khu/toyouserver/application/GroupService.java
index 476d0a9..ae06406 100644
--- a/src/main/java/slvtwn/khu/toyouserver/application/GroupService.java
+++ b/src/main/java/slvtwn/khu/toyouserver/application/GroupService.java
@@ -1,33 +1,36 @@
 package slvtwn.khu.toyouserver.application;
 
-import java.util.List;
 import org.springframework.stereotype.Service;
-import slvtwn.khu.toyouserver.domain.GroupRepository;
-import slvtwn.khu.toyouserver.presentation.GroupMemberResponse;
-import slvtwn.khu.toyouserver.presentation.GroupResponse;
+import org.springframework.transaction.annotation.Transactional;
+import slvtwn.khu.toyouserver.common.ErrorType;
+import slvtwn.khu.toyouserver.domain.Group;
+import slvtwn.khu.toyouserver.domain.User;
+import slvtwn.khu.toyouserver.dto.GroupResponse;
+import slvtwn.khu.toyouserver.exception.ToyouException;
+import slvtwn.khu.toyouserver.persistance.GroupRepository;
+import slvtwn.khu.toyouserver.persistance.UserRepository;
 
 @Service
+@Transactional(readOnly = true)
 public class GroupService {
 
-	private final GroupRepository groupRepository;
+    private final GroupRepository groupRepository;
+    private final UserRepository userRepository;
 
-	private final UserService userService;
+    public GroupService(GroupRepository groupRepository, UserRepository userRepository) {
+        this.groupRepository = groupRepository;
+        this.userRepository = userRepository;
+    }
 
-	public GroupService(GroupRepository groupRepository, UserService userService) {
-		this.groupRepository = groupRepository;
-		this.userService = userService;
-	}
+    @Transactional
+    public GroupResponse registerUser(long groupId, long userId) {
+        Group group = groupRepository.findById(groupId)
+                .orElseThrow(() -> new ToyouException(ErrorType.GROUP_NOT_FOUND));
+        User user = userRepository.findById(userId)
+                .orElseThrow(() -> new ToyouException(ErrorType.USER_NOT_FOUND));
 
-	public GroupResponse registerUser(final long groupId, final long userId) {
-		final var group = groupRepository.getById(groupId);
-		final var user = userService.findById(userId);
-		// TODO : 그룹에 유저를 가입시킨다. 유저는 멤버로 등록된다.
+        // TODO : 그룹에 유저를 가입시킨다. 유저는 멤버로 등록된다.
 //		group.addMember(user);
-		return new GroupResponse(group.getId(), group.getName());
-	}
-
-	public List<GroupMemberResponse> findAllMembers(final long groupId) {
-		final var group = groupRepository.getById(groupId);
-		return List.of(new GroupMemberResponse(1L, 1L, "user1", "profile1"));
-	}
-}
\ No newline at end of file
+        return new GroupResponse(group.getId(), group.getName());
+    }
+}
diff --git a/src/main/java/slvtwn/khu/toyouserver/application/UserService.java b/src/main/java/slvtwn/khu/toyouserver/application/UserService.java
index 0d04de2..65db4ac 100644
--- a/src/main/java/slvtwn/khu/toyouserver/application/UserService.java
+++ b/src/main/java/slvtwn/khu/toyouserver/application/UserService.java
@@ -1,9 +1,11 @@
 package slvtwn.khu.toyouserver.application;
 
 import org.springframework.stereotype.Service;
+import slvtwn.khu.toyouserver.common.ErrorType;
 import slvtwn.khu.toyouserver.domain.User;
-import slvtwn.khu.toyouserver.domain.UserRepository;
-
+import slvtwn.khu.toyouserver.exception.ToyouException;
+import slvtwn.khu.toyouserver.persistance.UserRepository;
+import slvtwn.khu.toyouserver.dto.UserResponse;
 
 @Service
 public class UserService {
@@ -14,7 +16,10 @@ public UserService(UserRepository userRepository) {
 		this.userRepository = userRepository;
 	}
 
-	public User findById(final long userId) {
-		return userRepository.getById(userId);
+	public UserResponse findUser(Long userId) {
+		User user = userRepository.findById(userId)
+				.orElseThrow(() -> new ToyouException(ErrorType.USER_NOT_FOUND));
+
+		return new UserResponse(user.getId(), user.getName(), user.getProfilePicture());
 	}
 }
diff --git a/src/main/java/slvtwn/khu/toyouserver/persistance/BaseTimeEntity.java b/src/main/java/slvtwn/khu/toyouserver/common/BaseTimeEntity.java
similarity index 93%
rename from src/main/java/slvtwn/khu/toyouserver/persistance/BaseTimeEntity.java
rename to src/main/java/slvtwn/khu/toyouserver/common/BaseTimeEntity.java
index 9cab087..71ec6a0 100644
--- a/src/main/java/slvtwn/khu/toyouserver/persistance/BaseTimeEntity.java
+++ b/src/main/java/slvtwn/khu/toyouserver/common/BaseTimeEntity.java
@@ -1,4 +1,4 @@
-package slvtwn.khu.toyouserver.persistance;
+package slvtwn.khu.toyouserver.common;
 
 import jakarta.persistence.Column;
 import jakarta.persistence.EntityListeners;
diff --git a/src/main/java/slvtwn/khu/toyouserver/common/ToyouResponse.java b/src/main/java/slvtwn/khu/toyouserver/common/ToyouResponse.java
new file mode 100644
index 0000000..2a12f77
--- /dev/null
+++ b/src/main/java/slvtwn/khu/toyouserver/common/ToyouResponse.java
@@ -0,0 +1,9 @@
+package slvtwn.khu.toyouserver.common;
+
+// TODO: 효율적인 예외처리 Wrapping 과정에 대해 고민
+public record ToyouResponse<T>(String code, T data) {
+
+    public static <T> ToyouResponse<T> success(T data) {
+        return new ToyouResponse<>("SUCCESS", data);
+    }
+}
diff --git a/src/main/java/slvtwn/khu/toyouserver/domain/Comment.java b/src/main/java/slvtwn/khu/toyouserver/domain/Comment.java
index 3c9fa8e..7204564 100644
--- a/src/main/java/slvtwn/khu/toyouserver/domain/Comment.java
+++ b/src/main/java/slvtwn/khu/toyouserver/domain/Comment.java
@@ -9,7 +9,7 @@
 import jakarta.persistence.ManyToOne;
 import lombok.AccessLevel;
 import lombok.NoArgsConstructor;
-import slvtwn.khu.toyouserver.persistance.BaseTimeEntity;
+import slvtwn.khu.toyouserver.common.BaseTimeEntity;
 
 @Entity
 @NoArgsConstructor(access = AccessLevel.PROTECTED)
diff --git a/src/main/java/slvtwn/khu/toyouserver/domain/Group.java b/src/main/java/slvtwn/khu/toyouserver/domain/Group.java
index 7bc4f9e..0cd4871 100644
--- a/src/main/java/slvtwn/khu/toyouserver/domain/Group.java
+++ b/src/main/java/slvtwn/khu/toyouserver/domain/Group.java
@@ -9,7 +9,7 @@
 import lombok.AccessLevel;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
-import slvtwn.khu.toyouserver.persistance.BaseTimeEntity;
+import slvtwn.khu.toyouserver.common.BaseTimeEntity;
 
 @Entity
 @Table(name = "groups")
diff --git a/src/main/java/slvtwn/khu/toyouserver/domain/GroupRepository.java b/src/main/java/slvtwn/khu/toyouserver/domain/GroupRepository.java
deleted file mode 100644
index 3498677..0000000
--- a/src/main/java/slvtwn/khu/toyouserver/domain/GroupRepository.java
+++ /dev/null
@@ -1,24 +0,0 @@
-package slvtwn.khu.toyouserver.domain;
-
-import static slvtwn.khu.toyouserver.common.ErrorType.GROUP_NOT_FOUND;
-
-import java.util.Optional;
-import org.springframework.data.jpa.repository.JpaRepository;
-import org.springframework.stereotype.Repository;
-import org.springframework.transaction.annotation.Transactional;
-import slvtwn.khu.toyouserver.exception.ToyouException;
-
-@Repository
-public interface GroupRepository extends JpaRepository<Group, Long> {
-
-	@Transactional
-	Group save(Group group);
-
-	@Transactional(readOnly = true)
-	Optional<Group> findById(long id);
-
-	@Transactional(readOnly = true)
-	default Group getById(final long id) {
-		return findById(id).orElseThrow(() -> new ToyouException(GROUP_NOT_FOUND));
-	}
-}
diff --git a/src/main/java/slvtwn/khu/toyouserver/domain/Member.java b/src/main/java/slvtwn/khu/toyouserver/domain/Member.java
index a6ade45..c47ecb1 100644
--- a/src/main/java/slvtwn/khu/toyouserver/domain/Member.java
+++ b/src/main/java/slvtwn/khu/toyouserver/domain/Member.java
@@ -9,26 +9,26 @@
 import lombok.AccessLevel;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
-import slvtwn.khu.toyouserver.persistance.BaseTimeEntity;
+import slvtwn.khu.toyouserver.common.BaseTimeEntity;
 
 @Entity
 @NoArgsConstructor(access = AccessLevel.PROTECTED)
 @Getter
 public class Member extends BaseTimeEntity {
 
-	@Id
-	@GeneratedValue
-	private Long id;
+    @Id
+    @GeneratedValue
+    private Long id;
 
-	@ManyToOne(fetch = FetchType.LAZY)
-	@JoinColumn(name = "user_id")
-	private User user;
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "user_id")
+    private User user;
 
-	@ManyToOne(fetch = FetchType.LAZY)
-	@JoinColumn(name = "group_id")
-	private Group group;
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "group_id")
+    private Group group;
 
-	public Member(Group group) {
-		this.group = group;
-	}
+    public Member(Group group) {
+        this.group = group;
+    }
 }
diff --git a/src/main/java/slvtwn/khu/toyouserver/domain/RollingPaper.java b/src/main/java/slvtwn/khu/toyouserver/domain/RollingPaper.java
index 1c0338a..08b0353 100644
--- a/src/main/java/slvtwn/khu/toyouserver/domain/RollingPaper.java
+++ b/src/main/java/slvtwn/khu/toyouserver/domain/RollingPaper.java
@@ -10,7 +10,7 @@
 import lombok.AccessLevel;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
-import slvtwn.khu.toyouserver.persistance.BaseTimeEntity;
+import slvtwn.khu.toyouserver.common.BaseTimeEntity;
 
 @Entity
 @NoArgsConstructor(access = AccessLevel.PROTECTED)
diff --git a/src/main/java/slvtwn/khu/toyouserver/domain/User.java b/src/main/java/slvtwn/khu/toyouserver/domain/User.java
index fc0306c..270b90a 100644
--- a/src/main/java/slvtwn/khu/toyouserver/domain/User.java
+++ b/src/main/java/slvtwn/khu/toyouserver/domain/User.java
@@ -8,7 +8,7 @@
 import lombok.AccessLevel;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
-import slvtwn.khu.toyouserver.persistance.BaseTimeEntity;
+import slvtwn.khu.toyouserver.common.BaseTimeEntity;
 
 @Entity
 @Table(name = "users")
diff --git a/src/main/java/slvtwn/khu/toyouserver/domain/UserRepository.java b/src/main/java/slvtwn/khu/toyouserver/domain/UserRepository.java
deleted file mode 100644
index 2a144c9..0000000
--- a/src/main/java/slvtwn/khu/toyouserver/domain/UserRepository.java
+++ /dev/null
@@ -1,21 +0,0 @@
-package slvtwn.khu.toyouserver.domain;
-
-import static slvtwn.khu.toyouserver.common.ErrorType.USER_NOT_FOUND;
-
-import java.util.Optional;
-import org.springframework.data.jpa.repository.JpaRepository;
-import org.springframework.stereotype.Repository;
-import org.springframework.transaction.annotation.Transactional;
-import slvtwn.khu.toyouserver.exception.ToyouException;
-
-@Repository
-public interface UserRepository extends JpaRepository<User, Long> {
-
-	@Transactional(readOnly = true)
-	Optional<User> findById(Long id);
-
-	@Transactional(readOnly = true)
-	default User getById(Long id) {
-		return findById(id).orElseThrow(() -> new ToyouException(USER_NOT_FOUND));
-	}
-}
diff --git a/src/main/java/slvtwn/khu/toyouserver/dto/GroupResponse.java b/src/main/java/slvtwn/khu/toyouserver/dto/GroupResponse.java
new file mode 100644
index 0000000..5d0c903
--- /dev/null
+++ b/src/main/java/slvtwn/khu/toyouserver/dto/GroupResponse.java
@@ -0,0 +1,4 @@
+package slvtwn.khu.toyouserver.dto;
+
+public record GroupResponse(Long id, String name) {
+}
diff --git a/src/main/java/slvtwn/khu/toyouserver/dto/UserResponse.java b/src/main/java/slvtwn/khu/toyouserver/dto/UserResponse.java
new file mode 100644
index 0000000..5ba3fdf
--- /dev/null
+++ b/src/main/java/slvtwn/khu/toyouserver/dto/UserResponse.java
@@ -0,0 +1,4 @@
+package slvtwn.khu.toyouserver.dto;
+
+public record UserResponse(Long id, String name, String imageUrl) {
+}
diff --git a/src/main/java/slvtwn/khu/toyouserver/exception/ToyouException.java b/src/main/java/slvtwn/khu/toyouserver/exception/ToyouException.java
index 414b487..4950d74 100644
--- a/src/main/java/slvtwn/khu/toyouserver/exception/ToyouException.java
+++ b/src/main/java/slvtwn/khu/toyouserver/exception/ToyouException.java
@@ -6,7 +6,8 @@
 
 @RequiredArgsConstructor
 @Getter
-public final class ToyouException extends RuntimeException {
+public class ToyouException extends RuntimeException {
+
 	private final ErrorType errorType;
 
 	public String code() {
diff --git a/src/main/java/slvtwn/khu/toyouserver/persistance/GroupRepository.java b/src/main/java/slvtwn/khu/toyouserver/persistance/GroupRepository.java
new file mode 100644
index 0000000..48015a1
--- /dev/null
+++ b/src/main/java/slvtwn/khu/toyouserver/persistance/GroupRepository.java
@@ -0,0 +1,7 @@
+package slvtwn.khu.toyouserver.persistance;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import slvtwn.khu.toyouserver.domain.Group;
+
+public interface GroupRepository extends JpaRepository<Group, Long> {
+}
diff --git a/src/main/java/slvtwn/khu/toyouserver/persistance/UserRepository.java b/src/main/java/slvtwn/khu/toyouserver/persistance/UserRepository.java
new file mode 100644
index 0000000..0126b83
--- /dev/null
+++ b/src/main/java/slvtwn/khu/toyouserver/persistance/UserRepository.java
@@ -0,0 +1,7 @@
+package slvtwn.khu.toyouserver.persistance;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import slvtwn.khu.toyouserver.domain.User;
+
+public interface UserRepository extends JpaRepository<User, Long> {
+}
diff --git a/src/main/java/slvtwn/khu/toyouserver/presentation/GroupController.java b/src/main/java/slvtwn/khu/toyouserver/presentation/GroupController.java
index 695c5b9..17c195f 100644
--- a/src/main/java/slvtwn/khu/toyouserver/presentation/GroupController.java
+++ b/src/main/java/slvtwn/khu/toyouserver/presentation/GroupController.java
@@ -1,21 +1,20 @@
 package slvtwn.khu.toyouserver.presentation;
 
+import lombok.RequiredArgsConstructor;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RestController;
 import slvtwn.khu.toyouserver.application.GroupService;
+import slvtwn.khu.toyouserver.dto.GroupResponse;
 
+@RequiredArgsConstructor
 @RestController
 public class GroupController {
 
-	private final GroupService groupService;
+    private final GroupService groupService;
 
-	public GroupController(GroupService groupService) {
-		this.groupService = groupService;
-	}
-
-	@PostMapping("/groups/{groupId}/members")
-	public GroupResponse registerMember(@PathVariable final long groupId) {
-		return groupService.registerMember(groupId);
-	}
+    @PostMapping("/groups/{groupId}/members")
+    public GroupResponse registerMember(@PathVariable long groupId) {
+        return groupService.registerUser(groupId, 1L); // TODO: user -> argumentResolver 등록 필요
+    }
 }
diff --git a/src/main/java/slvtwn/khu/toyouserver/presentation/GroupResponse.java b/src/main/java/slvtwn/khu/toyouserver/presentation/GroupResponse.java
deleted file mode 100644
index 238efe7..0000000
--- a/src/main/java/slvtwn/khu/toyouserver/presentation/GroupResponse.java
+++ /dev/null
@@ -1,7 +0,0 @@
-package slvtwn.khu.toyouserver.presentation;
-
-public record GroupResponse(
-		Long id,
-
-		String name) {
-}
\ No newline at end of file
diff --git a/src/main/java/slvtwn/khu/toyouserver/presentation/UserController.java b/src/main/java/slvtwn/khu/toyouserver/presentation/UserController.java
new file mode 100644
index 0000000..8c73635
--- /dev/null
+++ b/src/main/java/slvtwn/khu/toyouserver/presentation/UserController.java
@@ -0,0 +1,23 @@
+package slvtwn.khu.toyouserver.presentation;
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RestController;
+import slvtwn.khu.toyouserver.application.UserService;
+import slvtwn.khu.toyouserver.common.ToyouResponse;
+import slvtwn.khu.toyouserver.dto.UserResponse;
+
+@RequiredArgsConstructor
+@RestController
+public class UserController {
+
+    private final UserService userService;
+
+    @GetMapping("/users/{userId}")
+    public ToyouResponse<UserResponse> findUser(@PathVariable Long userId) {
+        UserResponse userResponse = userService.findUser(userId);
+
+        return ToyouResponse.success(userResponse);
+    }
+}
diff --git a/src/main/resources/application.yml b/src/main/resources/application.yml
index 9d366b8..d279fe1 100644
--- a/src/main/resources/application.yml
+++ b/src/main/resources/application.yml
@@ -1,17 +1,16 @@
 spring:
-  data-source:
-    url: jdbc:h2:mem:test
-    driver-class-name: org.h2.Driver
-    username: sa
-    password:
-
   jpa:
-    database: mysql
+#    database: mysql
     open-in-view: false
-    show-sql: true
-    database-platform: org.hibernate.dialect.H2Dialect
     generate-ddl: true
+    show-sql: true
     properties:
       hibernate:
         format_sql: true
-        ddl-auto: update
+
+  datasource:
+    url: jdbc:h2:mem:testdb
+    driver-class-name: org.h2.Driver
+    username: sa
+    password:
+
diff --git a/src/test/java/slvtwn/khu/toyouserver/user/service/UserServiceTest.java b/src/test/java/slvtwn/khu/toyouserver/user/service/UserServiceTest.java
new file mode 100644
index 0000000..06997ac
--- /dev/null
+++ b/src/test/java/slvtwn/khu/toyouserver/user/service/UserServiceTest.java
@@ -0,0 +1,42 @@
+package slvtwn.khu.toyouserver.user.service;
+
+import org.assertj.core.api.SoftAssertions;
+import org.junit.jupiter.api.DisplayNameGeneration;
+import org.junit.jupiter.api.DisplayNameGenerator;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.transaction.annotation.Transactional;
+import slvtwn.khu.toyouserver.application.UserService;
+import slvtwn.khu.toyouserver.domain.User;
+import slvtwn.khu.toyouserver.persistance.UserRepository;
+import slvtwn.khu.toyouserver.dto.UserResponse;
+
+@SuppressWarnings("NonAsciiCharacters")
+@DisplayNameGeneration(DisplayNameGenerator.ReplaceUnderscores.class)
+@SpringBootTest
+@Transactional
+class UserServiceTest {
+
+    @Autowired
+    private UserRepository userRepository;
+    @Autowired
+    private UserService userService;
+
+    @Test
+    void 유저를_조회할_수_있다() {
+        // given
+        User user = new User("teo", "www.profile-picture.com");
+        userRepository.save(user);
+
+        // when
+        UserResponse found = userService.findUser(user.getId());
+
+        // then
+        SoftAssertions.assertSoftly(softly -> {
+            softly.assertThat(user.getId()).isEqualTo(found.id());
+            softly.assertThat(user.getName()).isEqualTo(found.name());
+            softly.assertThat(user.getProfilePicture()).isEqualTo(found.imageUrl());
+        });
+    }
+}