diff --git a/src/main/java/org/sopt/seonyakServer/domain/member/service/MemberService.java b/src/main/java/org/sopt/seonyakServer/domain/member/service/MemberService.java
index 8f3297f..0062fb3 100644
--- a/src/main/java/org/sopt/seonyakServer/domain/member/service/MemberService.java
+++ b/src/main/java/org/sopt/seonyakServer/domain/member/service/MemberService.java
@@ -63,6 +63,7 @@ public void init() {
     }
 
     // JWT Access Token 생성
+    @Transactional
     public LoginSuccessResponse create(
             final String authorizationCode,
             final MemberLoginRequest loginRequest
@@ -73,7 +74,7 @@ public LoginSuccessResponse create(
     }
 
     // 소셜 플랫폼으로부터 해당 유저 정보를 받아옴
-    public MemberInfoResponse getMemberInfoResponse(
+    private MemberInfoResponse getMemberInfoResponse(
             final String authorizationCode,
             final MemberLoginRequest loginRequest
     ) {
@@ -106,14 +107,14 @@ private LoginSuccessResponse getTokenDto(final MemberInfoResponse memberInfoResp
         }
     }
 
-    public boolean isExistingMember(
+    private boolean isExistingMember(
             final SocialType socialType,
             final String socialId
     ) {
         return memberRepository.findBySocialTypeAndSocialId(socialType, socialId).isPresent();
     }
 
-    public Long getMemberIdBySocialId(
+    private Long getMemberIdBySocialId(
             final SocialType socialType,
             final String socialId
     ) {
@@ -124,13 +125,14 @@ public Long getMemberIdBySocialId(
         return member.getId();
     }
 
-    public LoginSuccessResponse getTokenByMemberId(final Long id) {
+    private LoginSuccessResponse getTokenByMemberId(final Long id) {
         MemberAuthentication memberAuthentication = new MemberAuthentication(id, null, null);
 
         return LoginSuccessResponse.of(jwtTokenProvider.issueAccessToken(memberAuthentication));
     }
 
     // 닉네임 유효성 검증
+    @Transactional(readOnly = true)
     public void validNickname(final NicknameRequest nicknameRequest) {
         if (!nicknameRequest.nickname().matches(NICKNAME_PATTERN)) { // 형식 체크
             throw new CustomException(ErrorType.INVALID_NICKNAME_ERROR);
@@ -168,6 +170,7 @@ public MemberJoinResponse patchMemberJoin(MemberJoinRequest memberJoinRequest) {
         );
     }
 
+    @Transactional
     public void sendMessage(SendCodeRequest sendCodeRequest) {
         Message message = new Message();
 
@@ -198,6 +201,7 @@ private String generateRandomNumber(int digitCount) {
     }
 
     // 인증번호 일치 여부 확인
+    @Transactional
     public void verifyCode(VerifyCodeRequest verifyCodeRequest) {
         String number = verifyCodeRequest.phoneNumber().replaceAll("-", "");
 
diff --git a/src/main/java/org/sopt/seonyakServer/global/auth/redis/service/CodeService.java b/src/main/java/org/sopt/seonyakServer/global/auth/redis/service/CodeService.java
index dcf8ae8..174cd31 100644
--- a/src/main/java/org/sopt/seonyakServer/global/auth/redis/service/CodeService.java
+++ b/src/main/java/org/sopt/seonyakServer/global/auth/redis/service/CodeService.java
@@ -14,7 +14,6 @@ public class CodeService {
 
     private final CodeRepository codeRepository;
 
-    @Transactional
     public void saveVerificationCode(
             final String phoneNumber,
             final String verificationCode
@@ -27,7 +26,6 @@ public void saveVerificationCode(
         );
     }
 
-    @Transactional(readOnly = true)
     public String findCodeByPhoneNumber(final String phoneNumber) {
         Code code = codeRepository.findByPhoneNumber(phoneNumber).orElseThrow(
                 () -> new CustomException(ErrorType.NO_VERIFICATION_REQUEST_HISTORY)