diff --git a/application/external-api-v2/src/main/java/com/namo/spring/application/external/api/schedule/controller/MeetingScheduleController.java b/application/external-api-v2/src/main/java/com/namo/spring/application/external/api/schedule/controller/MeetingScheduleController.java
index a5f105ea..9997fd0d 100644
--- a/application/external-api-v2/src/main/java/com/namo/spring/application/external/api/schedule/controller/MeetingScheduleController.java
+++ b/application/external-api-v2/src/main/java/com/namo/spring/application/external/api/schedule/controller/MeetingScheduleController.java
@@ -65,7 +65,6 @@ public ResponseDto<String> inviteMeetingParticipants(
             @PathVariable Long meetingScheduleId,
             @Valid @RequestBody MeetingScheduleRequest.PostMeetingParticipantsDto request,
             @AuthenticationPrincipal SecurityUserDetails memberInfo) {
-        validateParticipantCount(request.getParticipants().size());
         validateUniqueParticipantIds(memberInfo.getUserId(), request.getParticipants());
         meetingScheduleUsecase.createMeetingParticipants(meetingScheduleId, request, memberInfo);
         return ResponseDto.onSuccess("모임 초대 성공");
diff --git a/application/external-api-v2/src/main/java/com/namo/spring/application/external/api/schedule/service/ParticipantManageService.java b/application/external-api-v2/src/main/java/com/namo/spring/application/external/api/schedule/service/ParticipantManageService.java
index 4a852774..13444123 100644
--- a/application/external-api-v2/src/main/java/com/namo/spring/application/external/api/schedule/service/ParticipantManageService.java
+++ b/application/external-api-v2/src/main/java/com/namo/spring/application/external/api/schedule/service/ParticipantManageService.java
@@ -1,7 +1,6 @@
 package com.namo.spring.application.external.api.schedule.service;
 
 import com.namo.spring.application.external.api.record.enums.DiaryFilter;
-import com.namo.spring.application.external.api.schedule.dto.MeetingScheduleRequest;
 import com.namo.spring.application.external.global.utils.PeriodValidationUtils;
 import com.namo.spring.core.common.code.status.ErrorStatus;
 import com.namo.spring.db.mysql.domains.schedule.entity.Participant;
@@ -9,6 +8,7 @@
 import com.namo.spring.db.mysql.domains.schedule.exception.ParticipantException;
 import com.namo.spring.db.mysql.domains.schedule.exception.ScheduleException;
 import com.namo.spring.db.mysql.domains.schedule.service.ParticipantService;
+import com.namo.spring.db.mysql.domains.schedule.type.ParticipantRole;
 import com.namo.spring.db.mysql.domains.schedule.type.Period;
 import com.namo.spring.db.mysql.domains.user.entity.Friendship;
 import com.namo.spring.db.mysql.domains.user.entity.Member;
@@ -26,6 +26,8 @@
 import java.util.List;
 import java.util.stream.Collectors;
 
+import static com.namo.spring.application.external.global.utils.MeetingParticipantValidationUtils.validateParticipantCount;
+
 @Slf4j
 @Service
 @RequiredArgsConstructor
@@ -39,6 +41,8 @@ public void createScheduleOwner(Member member, Schedule schedule, Long categoryI
     }
 
     public void createMeetingParticipants(Member owner, Schedule schedule, List<Long> memberIds){
+        // 방장의 인원 제외하고 참여자 계산
+        validateParticipantCount(schedule.getParticipantCount() - 1 + memberIds.size());
         List<Member> participants = getFriendshipValidatedParticipants(owner.getId(), memberIds);
         participantMaker.makeMeetingScheduleParticipants(schedule, participants);
         List<String> participantNicknames = new ArrayList<>();
@@ -56,6 +60,22 @@ public List<Member> getFriendshipValidatedParticipants(Long ownerId, List<Long>
         return friends;
     }
 
+    /**
+     * 모임 일정에 대한 모든 참여자의 ID를 반환합니다,
+     * 반환 값에는 활성, 비활성 모든 상태의 참여자가 포함됩니다.
+     * 모임 일정 초대 인원 수를 검증하기 위해 사용합니다.
+     *
+     * @param scheduleId
+     * @return 모임 일정에 대한 모든 참여자의 ID 배열
+     */
+    public List<Long> getScheduleParticipantIds(Long scheduleId) {
+        return participantService.readParticipantsByScheduleId(scheduleId).stream()
+                .filter(participant -> participant.getIsOwner() == ParticipantRole.NON_OWNER.getValue())
+                .map(Participant::getMember)
+                .map(Member::getId)
+                .collect(Collectors.toList());
+    }
+
     /**
      * scheduleId와 memberId로 찾은
      * Participant 객체를 Member, Schedule과 함께 로딩하여 반환합니다.
@@ -74,14 +94,6 @@ public void deleteParticipant(Participant participant, Schedule schedule) {
         schedule.removeParticipant(participant.getMember().getNickname());
     }
 
-    public void updateMeetingScheduleParticipants(Long ownerId, Schedule schedule,
-            MeetingScheduleRequest.PatchMeetingScheduleDto dto) {
-        if (!dto.getParticipantsToAdd().isEmpty()) {
-            List<Member> participantsToAdd = getFriendshipValidatedParticipants(ownerId, dto.getParticipantsToAdd());
-            participantMaker.makeMeetingScheduleParticipants(schedule, participantsToAdd);
-        }
-    }
-
     private void removeParticipants(Schedule schedule, List<Participant> participants) {
         List<User> users = participants.stream().map(Participant::getUser).collect(Collectors.toList());
         schedule.removeParticipants(users.stream().map(User::getNickname).collect(Collectors.toList()));