diff --git a/umbba-api/src/main/java/sopt/org/umbba/api/service/qna/QnAService.java b/umbba-api/src/main/java/sopt/org/umbba/api/service/qna/QnAService.java
index a8c451cf..9f6846d5 100644
--- a/umbba-api/src/main/java/sopt/org/umbba/api/service/qna/QnAService.java
+++ b/umbba-api/src/main/java/sopt/org/umbba/api/service/qna/QnAService.java
@@ -184,14 +184,30 @@ public List<QnAListResponseDto> getQnaList(Long userId, Long sectionId) {
     public SingleQnAResponseDto getSingleQna(Long userId, Long qnaId) {
         User myUser = getUserById(userId);
         Parentchild parentchild = getParentchildByUser(myUser);
-
-        User opponentUser = getOpponentByParentchild(parentchild, userId);
         QnA targetQnA = getQnAById(qnaId);
         Question todayQuestion = targetQnA.getQuestion();
-
         List<QnA> qnaList = getQnAListByParentchild(parentchild);
 
-        return SingleQnAResponseDto.of(myUser, opponentUser, qnaList.indexOf(targetQnA) + 1, targetQnA, todayQuestion);
+        List<User> opponentUserList = userRepository.findUserByParentChild(parentchild)
+            .stream()
+            .filter(user -> !user.getId().equals(userId))
+            .collect(Collectors.toList());
+
+
+        if (opponentUserList.isEmpty()) {
+            boolean isFirstQnA = qnaList.get(0).equals(targetQnA);
+
+            if (isFirstQnA) {
+                return SingleQnAResponseDto.of(myUser, null, 1, targetQnA, todayQuestion);
+            } else {
+                throw new CustomException(ErrorType.PARENTCHILD_HAVE_NO_OPPONENT);
+            }
+        }
+
+        int index = qnaList.indexOf(targetQnA) + 1;
+        User opponentUser = opponentUserList.get(0);
+
+        return SingleQnAResponseDto.of(myUser, opponentUser, index, targetQnA, todayQuestion);
     }
 
     @Transactional