diff --git a/src/main/java/side/onetime/dto/event/response/GetMostPossibleTime.java b/src/main/java/side/onetime/dto/event/response/GetMostPossibleTime.java
index defc48b..75b331b 100644
--- a/src/main/java/side/onetime/dto/event/response/GetMostPossibleTime.java
+++ b/src/main/java/side/onetime/dto/event/response/GetMostPossibleTime.java
@@ -41,8 +41,8 @@ public static GetMostPossibleTime dateOf(Schedule schedule, List<String> possibl
         );
     }
 
-    public void updateEndTime(String endTime) {
-        new GetMostPossibleTime(
+    public GetMostPossibleTime updateEndTime(String endTime) {
+        return new GetMostPossibleTime(
                 this.timePoint,
                 this.startTime,
                 addThirtyMinutes(endTime),
diff --git a/src/main/java/side/onetime/service/EventService.java b/src/main/java/side/onetime/service/EventService.java
index 2b23aa1..c004c12 100644
--- a/src/main/java/side/onetime/service/EventService.java
+++ b/src/main/java/side/onetime/service/EventService.java
@@ -224,13 +224,17 @@ private List<GetMostPossibleTime> buildMostPossibleTimes(Map<Schedule, List<Stri
             List<String> curNames = entry.getValue();
 
             if (curNames.size() == mostPossibleCnt) {
+                // 이전 시간대와 병합 가능한 경우
                 if (canMergeWithPrevious(previousTime, schedule, curNames, category)) {
-                    previousTime.updateEndTime(schedule.getTime());
+                    // 종료 시간을 더해 업데이트
+                    previousTime = previousTime.updateEndTime(schedule.getTime());
+                    mostPossibleTimes.set(mostPossibleTimes.size() - 1, previousTime);
                 } else {
                     List<String> impossibleNames = allMembersName.stream()
                             .filter(name -> !curNames.contains(name))
                             .toList();
 
+                    // 새로운 시간대를 추가
                     GetMostPossibleTime newTime = createMostPossibleTime(schedule, curNames, impossibleNames, category);
                     mostPossibleTimes.add(newTime);
                     previousTime = newTime;