diff --git a/src/main/java/com/yello/server/domain/user/entity/User.java b/src/main/java/com/yello/server/domain/user/entity/User.java
index 003a638e..4bcdf736 100644
--- a/src/main/java/com/yello/server/domain/user/entity/User.java
+++ b/src/main/java/com/yello/server/domain/user/entity/User.java
@@ -7,6 +7,7 @@
 import com.yello.server.domain.group.entity.School;
 import com.yello.server.global.common.dto.AuditingTimeEntity;
 import java.time.LocalDateTime;
+import java.util.Objects;
 import javax.persistence.Column;
 import javax.persistence.Convert;
 import javax.persistence.Entity;
@@ -121,7 +122,7 @@ public static User of(SignUpRequest signUpRequest, School group) {
             .group(group)
             .groupAdmissionYear(signUpRequest.groupAdmissionYear())
             .email(signUpRequest.email())
-            .deviceToken(signUpRequest.deviceToken().isEmpty() ? null : signUpRequest.deviceToken())
+            .deviceToken(Objects.equals(signUpRequest.deviceToken(), "") ? null : signUpRequest.deviceToken())
             .subscribe(Subscribe.NORMAL)
             .ticketCount(0)
             .build();
@@ -182,7 +183,7 @@ public String getDeviceToken() {
     }
 
     public void setDeviceToken(String deviceToken) {
-        if (deviceToken.isEmpty()) {
+        if (Objects.equals(deviceToken, "")) {
             this.deviceToken = null;
         } else {
             this.deviceToken = deviceToken;