diff --git a/src/main/java/com/mangkyu/employment/interview/app/quiz/converter/QuizDtoConverter.java b/src/main/java/com/mangkyu/employment/interview/app/quiz/converter/QuizDtoConverter.java
index 6996c3d..ede6d74 100644
--- a/src/main/java/com/mangkyu/employment/interview/app/quiz/converter/QuizDtoConverter.java
+++ b/src/main/java/com/mangkyu/employment/interview/app/quiz/converter/QuizDtoConverter.java
@@ -8,6 +8,7 @@ import com.mangkyu.employment.interview.app.quiz.entity.Quiz;
 import com.mangkyu.employment.interview.enums.common.EnumMapperValue;
 import com.mangkyu.employment.interview.enums.value.QuizLevel;
 import lombok.NoArgsConstructor;
+import org.apache.commons.lang3.StringUtils;
 
 import java.sql.Timestamp;
 import java.util.List;
@@ -61,7 +62,7 @@ public final class QuizDtoConverter {
 
     private static String getAnswerResourceId(final Quiz quiz) {
         return (quiz.getAnswer() == null)
-                ? null
+                ? StringUtils.EMPTY
                 : quiz.getAnswer().getResourceId();
     }
 
diff --git a/src/main/java/com/mangkyu/employment/interview/app/quiz/dto/GetQuizResponse.java b/src/main/java/com/mangkyu/employment/interview/app/quiz/dto/GetQuizResponse.java
index 27aac7f..0398c65 100644
--- a/src/main/java/com/mangkyu/employment/interview/app/quiz/dto/GetQuizResponse.java
+++ b/src/main/java/com/mangkyu/employment/interview/app/quiz/dto/GetQuizResponse.java
@@ -14,8 +14,6 @@ import java.util.List;
 public class GetQuizResponse {
 
     private final String resourceId;
-
-    @JsonInclude(JsonInclude.Include.NON_NULL)
     private final String answerResourceId;
 
     private final String title;
diff --git a/src/test/java/com/mangkyu/employment/interview/app/quiz/converter/QuizDtoConverterTest.java b/src/test/java/com/mangkyu/employment/interview/app/quiz/converter/QuizDtoConverterTest.java
index 1a5690b..6ca6926 100644
--- a/src/test/java/com/mangkyu/employment/interview/app/quiz/converter/QuizDtoConverterTest.java
+++ b/src/test/java/com/mangkyu/employment/interview/app/quiz/converter/QuizDtoConverterTest.java
@@ -8,6 +8,7 @@ import com.mangkyu.employment.interview.app.quiz.entity.Quiz;
 import com.mangkyu.employment.interview.enums.common.EnumMapperType;
 import com.mangkyu.employment.interview.enums.common.EnumMapperValue;
 import com.mangkyu.employment.interview.testutils.EntityCreationUtils;
+import org.apache.commons.lang3.StringUtils;
 import org.junit.jupiter.api.Test;
 
 import java.sql.Timestamp;
@@ -83,7 +84,7 @@ class QuizDtoConverterTest {
         assertThat(result.getQuizLevelList().size()).isEqualTo(quiz.getQuizLevel().size());
         assertThat(result.getCreatedAt()).isEqualTo(Timestamp.valueOf(quiz.getCreatedAt()).getTime());
         assertThat(result.getCategory().getCode()).isEqualTo(enumMapperValue(quiz.getQuizCategory()).getCode());
-        assertThat(result.getAnswerResourceId()).isNull();
+        assertThat(result.getAnswerResourceId()).isEqualTo(StringUtils.EMPTY);
     }
 
     @Test
@@ -119,7 +120,7 @@ class QuizDtoConverterTest {
         assertThat(result.getQuizLevelList().size()).isEqualTo(quiz.getQuizLevel().size());
         assertThat(result.getCreatedAt()).isEqualTo(Timestamp.valueOf(quiz.getCreatedAt()).getTime());
         assertThat(result.getCategory()).isNull();
-        assertThat(result.getAnswerResourceId()).isNull();
+        assertThat(result.getAnswerResourceId()).isEqualTo(StringUtils.EMPTY);
     }
 
     private EnumMapperValue enumMapperValue(final EnumMapperType enumMapperType) {