diff --git a/src/main/java/in/koreatech/koin/domain/graduation/service/GraduationService.java b/src/main/java/in/koreatech/koin/domain/graduation/service/GraduationService.java
index 55daa73d33..9098cab40f 100644
--- a/src/main/java/in/koreatech/koin/domain/graduation/service/GraduationService.java
+++ b/src/main/java/in/koreatech/koin/domain/graduation/service/GraduationService.java
@@ -600,7 +600,7 @@ private TimetableLecture createTimetableLecture(GradeExcelData data, Lecture lec
         TimetableFrame graduationFrame, CourseType courseType, GeneralEducationArea generalEducationArea) {
         return TimetableLecture.builder()
             .classTitle(data.classTitle())
-            .classTime(lecture != null ? lecture.getClassTime() : null)
+            .classTime(lecture != null ? lecture.getClassTime() : "[]")
             .professor(data.professor())
             .grades(data.credit())
             .isDeleted(false)
diff --git a/src/main/java/in/koreatech/koin/domain/timetableV3/dto/response/LectureInfoResponse.java b/src/main/java/in/koreatech/koin/domain/timetableV3/dto/response/LectureInfoResponse.java
index 6e4f12b97b..e9587ce0dc 100644
--- a/src/main/java/in/koreatech/koin/domain/timetableV3/dto/response/LectureInfoResponse.java
+++ b/src/main/java/in/koreatech/koin/domain/timetableV3/dto/response/LectureInfoResponse.java
@@ -77,6 +77,9 @@ public static List<LectureInfoResponse> getCustomLectureInfo(String classTime, S
         }
 
         List<Integer> classTimes = parseToIntegerList(classTime);
+        if (classTimes.isEmpty()) {
+            return Collections.emptyList();
+        }
         List<LectureInfoResponse> response = new ArrayList<>();
 
         List<String> classPlaces = getClassPlaces(classPlace, classTimes);