diff --git a/src/main/java/com/amcamp/domain/task/domain/Task.java b/src/main/java/com/amcamp/domain/task/domain/Task.java
index 157d050a..aa010023 100644
--- a/src/main/java/com/amcamp/domain/task/domain/Task.java
+++ b/src/main/java/com/amcamp/domain/task/domain/Task.java
@@ -89,9 +89,12 @@ public void updateTaskBasicInfo(TaskBasicInfoUpdateRequest request) {
     }
 
     public void updateTaskStatus() {
-        if (this.taskStatus != TaskStatus.COMPLETED) this.taskStatus = TaskStatus.COMPLETED;
-        else {
+        if (this.taskStatus != TaskStatus.COMPLETED) {
+            this.taskStatus = TaskStatus.COMPLETED;
+            this.dueDt = LocalDate.now();
+        } else {
             this.taskStatus = TaskStatus.ON_GOING;
+            this.dueDt = null;
         }
     }
 
diff --git a/src/test/java/com/amcamp/domain/task/TaskServiceTest.java b/src/test/java/com/amcamp/domain/task/TaskServiceTest.java
index cb9a0593..8821b0f8 100644
--- a/src/test/java/com/amcamp/domain/task/TaskServiceTest.java
+++ b/src/test/java/com/amcamp/domain/task/TaskServiceTest.java
@@ -271,6 +271,7 @@ class 태스크_수정_시 {
         }
 
         @Test
+        @Transactional
         void 정상적으로_완료된_태스크를_미완료처리한다() {
             // given
             TaskCreateRequest taskRequest =
@@ -283,12 +284,14 @@ class 태스크_수정_시 {
                             .orElseThrow(() -> new CommonException(TaskErrorCode.TASK_NOT_FOUND));
 
             task.assignTask(participant);
-            task.updateTaskStatus();
 
-            // when
+            // when & then
             task.updateTaskStatus();
+            assertThat(task.getDueDt()).isEqualTo(LocalDate.now());
 
-            // then
+            // when & then
+            task.updateTaskStatus();
+            assertThat(task.getDueDt()).isNull();
             assertThat(task.getTaskStatus()).isEqualTo(TaskStatus.ON_GOING);
         }