diff --git a/server/handler/applicants.go b/server/handler/applicants.go
index b0d77ae..0a41ee2 100644
--- a/server/handler/applicants.go
+++ b/server/handler/applicants.go
@@ -1,6 +1,7 @@
 package handler
 
 import (
+	"fmt"
 	"net/http"
 
 	"github.com/google/uuid"
@@ -32,7 +33,7 @@ func (h *Handler) GetEventsEventIDApplicants(ctx echo.Context, eventID api.Event
 	res := make(api.GetEventApplicantsResponse, 0, len(dateOptions))
 	for traQID, dateIDs := range dateOptions {
 		res = append(res, api.Applicant{
-			TraqID: &traQID,
+			TraqID:        &traQID,
 			DateOptionIDs: &dateIDs,
 		})
 	}
@@ -45,24 +46,36 @@ func (h *Handler) PostEventsEventIDApplicants(ctx echo.Context, eventID api.Even
 	if err := ctx.Bind(&req); err != nil {
 		return echo.NewHTTPError(http.StatusBadRequest, err)
 	}
+	if len(*req.DateOptionIDs) == 0 {
+		return ctx.NoContent(http.StatusOK)
+	}
+	// eventIDがeventDateIDのそれぞれの値が齟齬がないか確認
+	err := h.repo.ValidateEventDateIDsFromEventID(eventID, *req.DateOptionIDs)
+	if err != nil {
+		return echo.NewHTTPError(http.StatusBadRequest, fmt.Sprintf("invalid event ID and DateOptionIDs: %v", err))
+	}
+
+	traQID := ctx.Get(traQIDKey).(string)
 
-	dateVotes := []model.DateVote{}
+	// traqIDがeventDateIDのそれぞれの値が齟齬がないか確認
+	err = h.repo.ValidateEventDateIDsFromTraqID(traQID, *req.DateOptionIDs)
+	if err != nil {
+		return echo.NewHTTPError(http.StatusBadRequest, fmt.Sprintf("already exists traqID and DateOptionIDs: %v", err))
+	}
+
+	dateVotes := make([]model.DateVote, 0, len(*req.DateOptionIDs))
 	for _, dateOption := range *req.DateOptionIDs {
 		id, err := uuid.NewV7()
 		if err != nil {
 			return echo.NewHTTPError(http.StatusInternalServerError, err)
 		}
-		
-		traQID := ctx.Get(traQIDKey).(string)
 		dateVotes = append(dateVotes, model.DateVote{
-			ID: id,
-			EventID: eventID,
-			TraQID:  traQID,
-			DateID:  dateOption,
+			ID:     id,
+			TraQID: traQID,
+			DateID: dateOption,
 		})
 	}
-
-	err := h.repo.CreateDateVotes(dateVotes)
+	err = h.repo.CreateDateVotes(dateVotes)
 	if err != nil {
 		return echo.NewHTTPError(http.StatusInternalServerError, err)
 	}
diff --git a/server/model/date_vote.go b/server/model/date_vote.go
index ba62604..018d9b9 100644
--- a/server/model/date_vote.go
+++ b/server/model/date_vote.go
@@ -8,7 +8,6 @@ import (
 
 type DateVote struct {
 	ID        uuid.UUID `db:"id"`
-	EventID   uuid.UUID `db:"event_id"`
 	TraQID    string    `db:"traq_id"`
 	DateID    uuid.UUID `db:"event_date_id"`
 	CreatedAt time.Time `db:"created_at"`
@@ -38,6 +37,6 @@ func (repo *Repository) CreateDateVotes(votes []DateVote) error {
 	if err != nil {
 		return err
 	}
-	
+
 	return tx.Commit()
 }
diff --git a/server/model/event_date.go b/server/model/event_date.go
index 001999f..7dc5b80 100644
--- a/server/model/event_date.go
+++ b/server/model/event_date.go
@@ -1,9 +1,12 @@
 package model
 
 import (
+	"fmt"
+	"log"
 	"time"
 
 	"github.com/google/uuid"
+	"github.com/jmoiron/sqlx"
 )
 
 type EventDate struct {
@@ -38,3 +41,38 @@ func (repo *Repository) CreateEventDates(dates []EventDate) error {
 
 	return tx.Commit()
 }
+
+func (repo *Repository) ValidateEventDateIDsFromEventID(eventID uuid.UUID, dateIDs []uuid.UUID) error {
+	var count int
+	query, args, err := sqlx.In("SELECT COUNT(*) FROM event_dates WHERE event_id = ? AND id IN (?)", eventID, dateIDs)
+	if err != nil {
+		log.Println("Error creating SQL query")
+		return err
+	}
+	err = repo.db.Get(&count, query, args...)
+	if err != nil {
+		log.Println("Error getting count from event_dates")
+		return err
+	}
+	if count != len(dateIDs) {
+		return fmt.Errorf("invalid date IDs: %v", dateIDs)
+	}
+	return nil
+}
+
+func (repo *Repository) ValidateEventDateIDsFromTraqID(traQID string, dateIDs []uuid.UUID) error {
+	// すでにtraQIDとdateIDsの組み合わせが存在するか確認
+	var count int
+	query, args, err := sqlx.In("SELECT COUNT(*) FROM date_votes WHERE traq_id = ? AND event_date_id IN (?)", traQID, dateIDs)
+	if err != nil {
+		return err
+	}
+	err = repo.db.Get(&count, query, args...)
+	if err != nil {
+		return err
+	}
+	if count > 0 {
+		return fmt.Errorf("invalid date IDs: %v", dateIDs)
+	}
+	return nil
+}