diff --git a/backend/src/main/java/harustudy/backend/content/service/ContentService.java b/backend/src/main/java/harustudy/backend/content/service/ContentService.java
index 9c3cc1bd..2c6af045 100644
--- a/backend/src/main/java/harustudy/backend/content/service/ContentService.java
+++ b/backend/src/main/java/harustudy/backend/content/service/ContentService.java
@@ -1,6 +1,7 @@
 package harustudy.backend.content.service;
 
 import harustudy.backend.auth.dto.AuthMember;
+import harustudy.backend.auth.exception.AuthorizationException;
 import harustudy.backend.content.domain.Content;
 import harustudy.backend.content.dto.ContentResponse;
 import harustudy.backend.content.dto.ContentsResponse;
@@ -11,6 +12,7 @@
 import harustudy.backend.member.domain.Member;
 import harustudy.backend.member.repository.MemberRepository;
 import harustudy.backend.participant.domain.Participant;
+import harustudy.backend.participant.exception.ParticipantNotFoundException;
 import harustudy.backend.participant.repository.ParticipantRepository;
 import harustudy.backend.study.domain.Study;
 import harustudy.backend.study.repository.StudyRepository;
@@ -33,16 +35,34 @@ public class ContentService {
     @Transactional(readOnly = true)
     public ContentsResponse findContentsWithFilter(AuthMember authMember, Long studyId,
                                                    Long participantId, Integer cycle) {
-        Participant participant = participantRepository.findByIdIfExists(participantId);
         Study study = studyRepository.findByIdIfExists(studyId);
+        List<Participant> participants = participantRepository.findByStudy(study);
         Member member = memberRepository.findByIdIfExists(authMember.id());
 
-        participant.validateIsCreatedByMember(member);
-        participant.validateIsBelongsTo(study);
+        validateMemberIncludedIn(participants, member);
+        Participant participant = findParticipantById(participants, participantId);
 
         return getContentsResponseByCycleFilter(cycle, participant);
     }
 
+    private void validateMemberIncludedIn(List<Participant> participants, Member member) {
+        if (isMemberNotIncludedInParticipants(member, participants)) {
+            throw new AuthorizationException();
+        }
+    }
+
+    private boolean isMemberNotIncludedInParticipants(Member member, List<Participant> participants) {
+        return participants.stream()
+                .noneMatch(participant -> participant.isCreatedBy(member));
+    }
+
+    private Participant findParticipantById(List<Participant> participants, Long participantId) {
+        return participants.stream()
+                .filter(participant -> participant.isSameId(participantId))
+                .findFirst()
+                .orElseThrow(ParticipantNotFoundException::new);
+    }
+
     private ContentsResponse getContentsResponseByCycleFilter(Integer cycle, Participant participant) {
         List<Content> contents = participant.getContents();
         if (Objects.isNull(cycle)) {
diff --git a/backend/src/main/java/harustudy/backend/participant/domain/Participant.java b/backend/src/main/java/harustudy/backend/participant/domain/Participant.java
index 12cbd01f..e13c8a99 100644
--- a/backend/src/main/java/harustudy/backend/participant/domain/Participant.java
+++ b/backend/src/main/java/harustudy/backend/participant/domain/Participant.java
@@ -76,22 +76,22 @@ public void generateContents(int totalCycle) {
         }
     }
 
+    public boolean isSameId(Long id) {
+        return this.id.equals(id);
+    }
+
     public boolean isParticipantOf(Study study) {
         return this.study.getId().equals(study.getId());
     }
 
-    public boolean isNotCreatedBy(Member member) {
-        return !this.member.getId().equals(member.getId());
+    public boolean isCreatedBy(Member member) {
+        return this.member.getId().equals(member.getId());
     }
 
     public boolean hasSameNicknameWith(Participant participant) {
         return this.nickname.equals(participant.nickname);
     }
 
-    public boolean isNotIncludedIn(Study other) {
-        return !study.getId().equals(other.getId());
-    }
-
     public void validateIsHost() {
         if (!isHost) {
             throw new ParticipantIsNotHostException();
@@ -105,7 +105,7 @@ public void validateIsBelongsTo(Study study) {
     }
 
     public void validateIsCreatedByMember(Member member) {
-        if (isNotCreatedBy(member)) {
+        if (!isCreatedBy(member)) {
             throw new AuthorizationException();
         }
     }
diff --git a/backend/src/test/java/harustudy/backend/content/service/ContentServiceTest.java b/backend/src/test/java/harustudy/backend/content/service/ContentServiceTest.java
index 57ab8044..3c559059 100644
--- a/backend/src/test/java/harustudy/backend/content/service/ContentServiceTest.java
+++ b/backend/src/test/java/harustudy/backend/content/service/ContentServiceTest.java
@@ -6,6 +6,7 @@
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 
 import harustudy.backend.auth.dto.AuthMember;
+import harustudy.backend.auth.exception.AuthorizationException;
 import harustudy.backend.content.domain.Content;
 import harustudy.backend.content.dto.ContentResponse;
 import harustudy.backend.content.dto.ContentsResponse;
@@ -45,6 +46,7 @@ class ContentServiceTest {
 
     private Study study;
     private Member member;
+    private Member member2;
     private Participant participant;
     private Content content;
 
@@ -52,12 +54,13 @@ class ContentServiceTest {
     void setUp() {
         study = new Study("studyName", 1, 20);
         member = new Member("nickname", "email", "imageUrl", LoginType.GUEST);
+        member2 = new Member("nickname2", "email2", "imageUrl2", LoginType.GUEST);
         participant = Participant.createParticipantOfStudy(study, member, "nickname");
-
         content = new Content(participant, 1);
 
         entityManager.persist(study);
         entityManager.persist(member);
+        entityManager.persist(member2);
         entityManager.persist(participant);
         entityManager.persist(content);
 
@@ -224,6 +227,26 @@ void setUp() {
         assertThat(content).isEqualTo(expectedContentResponses);
     }
 
+    @Test
+    void 스터디원은_같은_스터디_내_다른_멤버의_콘텐츠를_조회할_수_있다() {
+        // given
+        AuthMember authMember = new AuthMember(member.getId());
+        Participant participant2 = Participant.createParticipantOfStudy(study, member2, "nickname2");
+        Content contentOfMember2 = new Content(participant2, 1);
+
+        entityManager.persist(participant2);
+        entityManager.persist(contentOfMember2);
+
+        EntityManagerUtil.flushAndClearContext(entityManager);
+
+        // when
+        ContentsResponse contentsWithFilter = contentService.findContentsWithFilter(authMember,
+                study.getId(), participant2.getId(), null);
+
+        // then
+        assertThat(contentsWithFilter.content().size()).isEqualTo(1);
+    }
+
     @Test
     void 스터디에_참여한_특정_스터디원의_콘텐츠를_조회시_스터디가_없으면_예외를_던진다() {
         // given
@@ -247,4 +270,14 @@ void setUp() {
                         study.getId(), 999L, null))
                 .isInstanceOf(ParticipantNotFoundException.class);
     }
+
+    @Test
+    void 같은_스터디에_참여하지_않은_멤버가_다른_스터디_멤버의_콘텐츠를_조회하면_예외를_던진다() {
+        // given
+        AuthMember authMember = new AuthMember(member2.getId());
+
+        // when, then
+        assertThatThrownBy(() -> contentService.findContentsWithFilter(authMember,
+                study.getId(), participant.getId(), null)).isInstanceOf(AuthorizationException.class);
+    }
 }