diff --git a/src/main/java/com/example/mate/common/error/ErrorCode.java b/src/main/java/com/example/mate/common/error/ErrorCode.java
index 1e7b7d0b..36c65b3e 100644
--- a/src/main/java/com/example/mate/common/error/ErrorCode.java
+++ b/src/main/java/com/example/mate/common/error/ErrorCode.java
@@ -130,6 +130,7 @@ public enum ErrorCode {
     ALREADY_JOINED_CHAT_ROOM(HttpStatus.BAD_REQUEST, "CHAT004", "이미 참여 중인 채팅방입니다."),
     CHAT_ROOM_CLOSED(HttpStatus.BAD_REQUEST, "CHAT005", "종료된 채팅방입니다."),
     CHAT_ROOM_ACCESS_DENIED(HttpStatus.FORBIDDEN, "CHAT006", "직관 완료된 채팅방에는 새로운 유저가 입장할 수 없습니다."),
+    CHAT_AUTHOR_JOIN_DENIED(HttpStatus.FORBIDDEN, "CHAT006", "방장은 채팅방 퇴장 시 재입장할 수 없습니다."),
     AUTHOR_LEAVE_NOT_ALLOWED(HttpStatus.FORBIDDEN, "CHAT007", "방장은 직관완료가 안된 채팅방에서 나갈 수 없습니다."),
     CHAT_ROOM_NOT_MESSAGEABLE(HttpStatus.FORBIDDEN, "CHAT008", "메세지 전송이 불가능한 채팅방입니다."),
 
diff --git a/src/main/java/com/example/mate/domain/mate/repository/VisitPartRepository.java b/src/main/java/com/example/mate/domain/mate/repository/VisitPartRepository.java
index f8421785..18108d5d 100644
--- a/src/main/java/com/example/mate/domain/mate/repository/VisitPartRepository.java
+++ b/src/main/java/com/example/mate/domain/mate/repository/VisitPartRepository.java
@@ -1,14 +1,14 @@
 package com.example.mate.domain.mate.repository;
 
-import com.example.mate.domain.mate.entity.Visit;
 import com.example.mate.domain.mate.entity.VisitPart;
 import com.example.mate.domain.mate.entity.VisitPartId;
 import com.example.mate.domain.member.entity.Member;
-import java.util.List;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.data.repository.query.Param;
 
+import java.util.List;
+
 public interface VisitPartRepository extends JpaRepository<VisitPart, VisitPartId> {
 
     int countByMember(Member member);
@@ -21,5 +21,12 @@ public interface VisitPartRepository extends JpaRepository<VisitPart, VisitPartI
             """)
     List<Member> findMembersByVisitIdExcludeMember(@Param("visitId") Long visitId, @Param("memberId") Long memberId);
 
-    boolean existsByVisitAndMember(Visit visit, Member member);
+    @Query("""
+            SELECT COUNT(vp) > 0
+            FROM VisitPart vp
+            WHERE vp.visit.id = :visitId
+            AND vp.member.id = :memberId
+            """)
+    boolean existsByVisitAndMember(@Param("visitId") Long visitId, @Param("memberId") Long memberId);
+
 }
diff --git a/src/main/java/com/example/mate/domain/mateChat/service/MateChatRoomService.java b/src/main/java/com/example/mate/domain/mateChat/service/MateChatRoomService.java
index b4b088d7..a4fbac69 100644
--- a/src/main/java/com/example/mate/domain/mateChat/service/MateChatRoomService.java
+++ b/src/main/java/com/example/mate/domain/mateChat/service/MateChatRoomService.java
@@ -103,8 +103,11 @@ private MateChatRoomResponse processChatRoomJoin(MateChatRoom chatRoom, Member m
     }
 
     private void validateChatRoomJoin(MatePost matePost, Member member) {
-        // 방장인 경우 모든 제한을 건너뜀
+        // 방장인 경우, 직관 완료 상태가 아닐 때만 입장 가능
         if (matePost.getAuthor().getId().equals(member.getId())) {
+            if (matePost.getStatus() == Status.VISIT_COMPLETE) {
+                throw new CustomException(ErrorCode.CHAT_AUTHOR_JOIN_DENIED);
+            }
             return;
         }
 
@@ -120,12 +123,13 @@ private void validateChatRoomJoin(MatePost matePost, Member member) {
         }
 
         // 3. 직관 완료 상태인 경우 접근 권한 검증
-        if (matePost.getStatus() == Status.VISIT_COMPLETE) {
+        if (matePost.getStatus() == Status.VISIT_COMPLETE && matePost.getVisit() != null) {
             boolean isVisitParticipant = visitPartRepository.existsByVisitAndMember(
-                    matePost.getVisit(), member);
-            boolean isAuthor = matePost.getAuthor().getId().equals(member.getId());
+                    matePost.getVisit().getId(),  // Visit 엔티티 대신 ID 전달
+                    member.getId()                 // Member 엔티티 대신 ID 전달
+            );
 
-            if (!isVisitParticipant && !isAuthor) {
+            if (!isVisitParticipant) {
                 throw new CustomException(ErrorCode.CHAT_ROOM_ACCESS_DENIED);
             }
         }