diff --git a/src/main/java/Donggukthon/santa/service/MemberSevice.java b/src/main/java/Donggukthon/santa/service/MemberSevice.java
index aa00fc7..0499cf8 100644
--- a/src/main/java/Donggukthon/santa/service/MemberSevice.java
+++ b/src/main/java/Donggukthon/santa/service/MemberSevice.java
@@ -47,8 +47,8 @@ public List<MemberNSubmissionResponseDTO> getDonatePeopleList() {
                     .name(member.getName())
                     .nickname(member.getNickname())
                     .gender(member.getGender())
-                    .phoneNumber(member.getPhoneNumber())
-                    .createdAt(member.getCreatedAt())
+                    .phone_number(member.getPhoneNumber())
+                    .created_at(member.getCreatedAt())
                     .build();
 
 
@@ -80,8 +80,8 @@ public Optional<CertificationResponseDTO> getDonatePersonCertification(Long id)
                 .name(member.get().getName())
                 .nickname(member.get().getNickname())
                 .gender(member.get().getGender())
-                .phoneNumber(member.get().getPhoneNumber())
-                .createdAt(member.get().getCreatedAt())
+                .phone_number(member.get().getPhoneNumber())
+                .created_at(member.get().getCreatedAt())
                 .build();
 
         CertificationResponseDTO certificationResponseDTO = CertificationResponseDTO.builder()
diff --git a/src/main/java/Donggukthon/santa/service/TreeService.java b/src/main/java/Donggukthon/santa/service/TreeService.java
index 79bf0cd..0577b52 100644
--- a/src/main/java/Donggukthon/santa/service/TreeService.java
+++ b/src/main/java/Donggukthon/santa/service/TreeService.java
@@ -68,7 +68,7 @@ private DecorationResponseDTO convertToDecorationResponseDTO(MemberDecorationRel
                 .location(decoration.getLocation())
 //                .color("Some color") // Populate appropriately
                 .scale(decoration.getScale())
-                .createdAt(decoration.getCreatedAt().toString())
+                .created_at(decoration.getCreatedAt().toString())
                 .build();
     }
 }
diff --git a/src/main/java/Donggukthon/santa/web/dto/response/DecorationResponseDTO.java b/src/main/java/Donggukthon/santa/web/dto/response/DecorationResponseDTO.java
index 0a2e126..314bd98 100644
--- a/src/main/java/Donggukthon/santa/web/dto/response/DecorationResponseDTO.java
+++ b/src/main/java/Donggukthon/santa/web/dto/response/DecorationResponseDTO.java
@@ -15,5 +15,5 @@ public class DecorationResponseDTO {
     private int scale;
     private int degree;
     private String floor;
-    private String createdAt;
+    private String created_at;
 }
diff --git a/src/main/java/Donggukthon/santa/web/dto/response/MemberDTO.java b/src/main/java/Donggukthon/santa/web/dto/response/MemberDTO.java
index 1a0cb9c..96968f9 100644
--- a/src/main/java/Donggukthon/santa/web/dto/response/MemberDTO.java
+++ b/src/main/java/Donggukthon/santa/web/dto/response/MemberDTO.java
@@ -22,8 +22,8 @@ public class MemberDTO {
     private String name;
     private String nickname;
     private String gender;
-    private String phoneNumber;
-    private LocalDateTime createdAt;
+    private String phone_number;
+    private LocalDateTime created_at;
 
     private List<Submission> submissions = new ArrayList<>();
     private List<DesignatedPerson> designatedpersons = new ArrayList<>();
@@ -36,8 +36,8 @@ public static MemberDTO toMemberDto(Member member){
         memberDto.setPassword(member.getPassword());
         memberDto.setName(member.getName());
         memberDto.setGender(member.getGender());
-        memberDto.setPhoneNumber(member.getPhoneNumber());
-        memberDto.setCreatedAt(member.getCreatedAt());
+        memberDto.setPhone_number(member.getPhoneNumber());
+        memberDto.setCreated_at(member.getCreatedAt());
 
         return memberDto;
     }
diff --git a/src/main/java/Donggukthon/santa/web/dto/response/MemberResponseDTO.java b/src/main/java/Donggukthon/santa/web/dto/response/MemberResponseDTO.java
index 0f25427..4291934 100644
--- a/src/main/java/Donggukthon/santa/web/dto/response/MemberResponseDTO.java
+++ b/src/main/java/Donggukthon/santa/web/dto/response/MemberResponseDTO.java
@@ -17,6 +17,6 @@ public final class MemberResponseDTO {
     private String name;
     private String nickname;
     private String gender;
-    private String phoneNumber;
-    private LocalDateTime createdAt;
+    private String phone_number;
+    private LocalDateTime created_at;
 }