diff --git a/src/main/java/com/project/trainingdiary/repository/WorkoutSessionRepository.java b/src/main/java/com/project/trainingdiary/repository/WorkoutSessionRepository.java
index 15e7bd9..867a192 100644
--- a/src/main/java/com/project/trainingdiary/repository/WorkoutSessionRepository.java
+++ b/src/main/java/com/project/trainingdiary/repository/WorkoutSessionRepository.java
@@ -15,7 +15,7 @@ public interface WorkoutSessionRepository extends JpaRepository<WorkoutSessionEn
   Optional<WorkoutSessionEntity> findByPtContract_TrainerAndId
       (TrainerEntity trainer, Long sessionId);
 
-  Optional<WorkoutSessionEntity> findByPtContract_TrainerAndSessionNumber
-      (TrainerEntity trainer, int sessionNumber);
+  Optional<WorkoutSessionEntity> findByPtContract_IdAndSessionNumber
+      (Long ptContractId, int sessionNumber);
 
 }
diff --git a/src/main/java/com/project/trainingdiary/service/WorkoutSessionService.java b/src/main/java/com/project/trainingdiary/service/WorkoutSessionService.java
index c11d596..6c79e18 100644
--- a/src/main/java/com/project/trainingdiary/service/WorkoutSessionService.java
+++ b/src/main/java/com/project/trainingdiary/service/WorkoutSessionService.java
@@ -84,7 +84,7 @@ public WorkoutSessionResponseDto createWorkoutSession(WorkoutSessionCreateReques
 
     // 세션 넘버에 대한 일지가 이미 존재하는지 확인
     workoutSessionRepository
-        .findByPtContract_TrainerAndSessionNumber(trainer, dto.getSessionNumber())
+        .findByPtContract_IdAndSessionNumber(ptContract.getId(), dto.getSessionNumber())
         .ifPresent(exist -> {
           throw new WorkoutSessionAlreadyExistException(dto.getSessionNumber());
         });
diff --git a/src/test/java/com/project/trainingdiary/service/WorkoutSessionServiceTest.java b/src/test/java/com/project/trainingdiary/service/WorkoutSessionServiceTest.java
index aaa59e9..66d1977 100644
--- a/src/test/java/com/project/trainingdiary/service/WorkoutSessionServiceTest.java
+++ b/src/test/java/com/project/trainingdiary/service/WorkoutSessionServiceTest.java
@@ -196,7 +196,7 @@ void testCreateWorkoutSessionSuccess() {
 
     when(ptContractRepository.findByTrainerIdAndTraineeId(trainer.getId(), trainee.getId()))
         .thenReturn(Optional.of(ptContract));
-    when(workoutSessionRepository.findByPtContract_TrainerAndSessionNumber(trainer, 1))
+    when(workoutSessionRepository.findByPtContract_IdAndSessionNumber(ptContract.getId(), 1))
         .thenReturn(Optional.empty());
     when(workoutTypeRepository.findById(workoutType.getId()))
         .thenReturn(Optional.of(workoutType));
@@ -219,7 +219,7 @@ void testCreateWorkoutSessionSuccess() {
     verify(ptContractRepository, times(1))
         .findByTrainerIdAndTraineeId(trainer.getId(), trainee.getId());
     verify(workoutSessionRepository, times(1))
-        .findByPtContract_TrainerAndSessionNumber(trainer, 1);
+        .findByPtContract_IdAndSessionNumber(ptContract.getId(), 1);
     verify(workoutTypeRepository, times(1)).findById(workoutType.getId());
     verify(workoutRepository, times(1)).save(workoutCaptor.capture());
     verify(workoutSessionRepository, times(1)).save(workoutSessionCaptor.capture());
@@ -258,7 +258,8 @@ void testCreateWorkoutSessionFailPtContractNotFound() {
     verify(ptContractRepository, times(1))
         .findByTrainerIdAndTraineeId(trainer.getId(), trainee.getId());
     verify(workoutSessionRepository, times(0))
-        .findByPtContract_TrainerAndSessionNumber(trainer, createRequestDto.getSessionNumber());
+        .findByPtContract_IdAndSessionNumber(ptContract.getId(),
+            createRequestDto.getSessionNumber());
     verify(workoutTypeRepository, times(0)).findById(workoutType.getId());
 
     ArgumentCaptor<WorkoutEntity> workoutCaptor = ArgumentCaptor.forClass(WorkoutEntity.class);
@@ -284,7 +285,8 @@ void testCreateWorkoutSessionFailureSessionAlreadyExists() {
     when(ptContractRepository.findByTrainerIdAndTraineeId(trainer.getId(), trainee.getId()))
         .thenReturn(Optional.of(ptContract));
     when(workoutSessionRepository
-        .findByPtContract_TrainerAndSessionNumber(trainer, createRequestDto.getSessionNumber()))
+        .findByPtContract_IdAndSessionNumber(ptContract.getId(),
+            createRequestDto.getSessionNumber()))
         .thenReturn(Optional.of(workoutSession));
 
     assertThrows(WorkoutSessionAlreadyExistException.class,
@@ -293,7 +295,8 @@ void testCreateWorkoutSessionFailureSessionAlreadyExists() {
     verify(ptContractRepository, times(1))
         .findByTrainerIdAndTraineeId(trainer.getId(), trainee.getId());
     verify(workoutSessionRepository, times(1))
-        .findByPtContract_TrainerAndSessionNumber(trainer, createRequestDto.getSessionNumber());
+        .findByPtContract_IdAndSessionNumber(ptContract.getId(),
+            createRequestDto.getSessionNumber());
     verify(workoutTypeRepository, times(0)).findById(workoutType.getId());
 
     ArgumentCaptor<WorkoutEntity> workoutCaptor = ArgumentCaptor.forClass(WorkoutEntity.class);
@@ -320,7 +323,8 @@ void testCreateWorkoutSessionFailWorkoutTypeNotFound() {
     when(ptContractRepository.findByTrainerIdAndTraineeId(trainer.getId(), trainee.getId()))
         .thenReturn(Optional.of(ptContract));
     when(workoutSessionRepository
-        .findByPtContract_TrainerAndSessionNumber(trainer, createRequestDto.getSessionNumber()))
+        .findByPtContract_IdAndSessionNumber(ptContract.getId(),
+            createRequestDto.getSessionNumber()))
         .thenReturn(Optional.empty());
     when(workoutTypeRepository.findById(workoutType.getId()))
         .thenReturn(Optional.empty());
@@ -331,7 +335,8 @@ void testCreateWorkoutSessionFailWorkoutTypeNotFound() {
     verify(ptContractRepository, times(1))
         .findByTrainerIdAndTraineeId(trainer.getId(), trainee.getId());
     verify(workoutSessionRepository, times(1))
-        .findByPtContract_TrainerAndSessionNumber(trainer, createRequestDto.getSessionNumber());
+        .findByPtContract_IdAndSessionNumber(ptContract.getId(),
+            createRequestDto.getSessionNumber());
     verify(workoutTypeRepository, times(1)).findById(workoutType.getId());
 
     ArgumentCaptor<WorkoutEntity> workoutCaptor = ArgumentCaptor.forClass(WorkoutEntity.class);