diff --git a/app/src/main/java/com/nativelap/heartguard/view/component/auth/AuthVerificationCodeInput.kt b/app/src/main/java/com/nativelap/heartguard/view/component/auth/AuthVerificationCodeInput.kt
index b9595a7c..d822438a 100644
--- a/app/src/main/java/com/nativelap/heartguard/view/component/auth/AuthVerificationCodeInput.kt
+++ b/app/src/main/java/com/nativelap/heartguard/view/component/auth/AuthVerificationCodeInput.kt
@@ -26,6 +26,7 @@ import androidx.compose.ui.focus.onFocusChanged
 import androidx.compose.ui.graphics.SolidColor
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.semantics.contentDescription
+import androidx.compose.ui.semantics.error
 import androidx.compose.ui.semantics.semantics
 import androidx.compose.ui.text.TextStyle
 import androidx.compose.ui.text.input.KeyboardType
@@ -42,6 +43,7 @@ internal fun AuthVerificationCodeInput(
     code: String,
     onCodeChange: (String) -> Unit,
     enabled: Boolean,
+    errorDescription: String? = null,
     modifier: Modifier = Modifier,
 ) {
     var isFocused by remember { mutableStateOf(false) }
@@ -59,7 +61,10 @@ internal fun AuthVerificationCodeInput(
                 .fillMaxWidth()
                 .keyboardInputBounds()
                 .onFocusChanged { focusState -> isFocused = focusState.isFocused }
-                .semantics { contentDescription = accessibilityDescription },
+                .semantics {
+                    contentDescription = accessibilityDescription
+                    errorDescription?.let { description -> error(description) }
+                },
         enabled = enabled,
         singleLine = true,
         keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.NumberPassword),
@@ -85,12 +90,12 @@ internal fun AuthVerificationCodeInput(
                                         color = MaterialTheme.colorScheme.surface,
                                         shape = RoundedCornerShape(CODE_CELL_CORNER_RADIUS),
                                     ).border(
-                                        width = if (isCurrentCell) 2.dp else 0.dp,
+                                        width = if (errorDescription != null || isCurrentCell) 2.dp else 0.dp,
                                         color =
-                                            if (isCurrentCell) {
-                                                MaterialTheme.extraColors.authPrimary
-                                            } else {
-                                                androidx.compose.ui.graphics.Color.Transparent
+                                            when {
+                                                errorDescription != null -> MaterialTheme.colorScheme.error
+                                                isCurrentCell -> MaterialTheme.extraColors.authPrimary
+                                                else -> androidx.compose.ui.graphics.Color.Transparent
                                             },
                                         shape = RoundedCornerShape(CODE_CELL_CORNER_RADIUS),
                                     ).padding(horizontal = 4.dp),
@@ -130,6 +135,7 @@ private fun AuthVerificationCodeInputPreview() {
             code = "123",
             onCodeChange = {},
             enabled = true,
+            errorDescription = stringResource(R.string.auth_signup_invalid_code_error),
         )
     }
 }
diff --git a/app/src/main/java/com/nativelap/heartguard/view/route/auth/AuthRoutes.kt b/app/src/main/java/com/nativelap/heartguard/view/route/auth/AuthRoutes.kt
index 85a01467..052c9cf7 100644
--- a/app/src/main/java/com/nativelap/heartguard/view/route/auth/AuthRoutes.kt
+++ b/app/src/main/java/com/nativelap/heartguard/view/route/auth/AuthRoutes.kt
@@ -180,6 +180,7 @@ internal fun HeartGuardSignUpRoute(
     val uiState by viewModel.uiState.collectAsStateWithLifecycle()
     val normalizedEmail = email.trim().lowercase(Locale.ROOT)
     val isCodeSentForCurrentEmail = uiState.emailForRequestedCode == normalizedEmail
+    val emailCodeRemainingSeconds = uiState.emailCodeRemainingSecondsByEmail[normalizedEmail] ?: 0
 
     BackHandler(
         enabled = uiState.isSubmitting || uiState.isRequestingEmailCode || uiState.isVerifyingEmailCode || step > 0,
@@ -275,9 +276,24 @@ internal fun HeartGuardSignUpRoute(
                 stringResource(R.string.auth_signup_registration_error)
             }
         }
+    val isInvalidVerificationCode =
+        uiState.failure == AppAccountSignUpFailure.INVALID_VERIFICATION_CODE
+    val isExpiredVerificationCode = isInvalidVerificationCode && emailCodeRemainingSeconds <= 0
     val statusMessage =
-        uiState.failureMessage?.takeIf { serverMessage -> serverMessage.isNotBlank() }
-            ?: fallbackStatusMessage
+        when {
+            isInvalidVerificationCode && !isExpiredVerificationCode -> {
+                fallbackStatusMessage
+            }
+
+            isExpiredVerificationCode -> {
+                stringResource(R.string.auth_signup_expired_code_error)
+            }
+
+            else -> {
+                uiState.failureMessage?.takeIf { serverMessage -> serverMessage.isNotBlank() }
+                    ?: fallbackStatusMessage
+            }
+        }
 
     AuthSignUpScreen(
         name = name,
@@ -289,10 +305,11 @@ internal fun HeartGuardSignUpRoute(
         isEmailCodeSent = isCodeSentForCurrentEmail,
         isEmailCodeResendBlocked =
             (uiState.emailCodeCooldownSecondsByEmail[normalizedEmail] ?: 0) > 0,
-        emailCodeRemainingSeconds = uiState.emailCodeRemainingSecondsByEmail[normalizedEmail] ?: 0,
+        emailCodeRemainingSeconds = emailCodeRemainingSeconds,
         isSubmitting = uiState.isSubmitting || uiState.isVerifyingEmailCode,
         statusMessage = statusMessage,
         isStatusError = uiState.failure != null,
+        isVerificationCodeError = isInvalidVerificationCode,
         step = step,
         onEvent = { event ->
             when (event) {
@@ -311,6 +328,9 @@ internal fun HeartGuardSignUpRoute(
                 }
 
                 is AuthSignUpScreenEvent.VerificationCodeChanged -> {
+                    if (uiState.failure == AppAccountSignUpFailure.INVALID_VERIFICATION_CODE) {
+                        viewModel.clearEmailCodeVerification()
+                    }
                     verificationCode = event.verificationCode.filter { digit -> digit in '0'..'9' }.take(6)
                 }
 
diff --git a/app/src/main/java/com/nativelap/heartguard/view/screen/auth/AuthSignUpScreen.kt b/app/src/main/java/com/nativelap/heartguard/view/screen/auth/AuthSignUpScreen.kt
index 91945e30..559010af 100644
--- a/app/src/main/java/com/nativelap/heartguard/view/screen/auth/AuthSignUpScreen.kt
+++ b/app/src/main/java/com/nativelap/heartguard/view/screen/auth/AuthSignUpScreen.kt
@@ -44,6 +44,9 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.focus.onFocusChanged
 import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.semantics.LiveRegionMode
+import androidx.compose.ui.semantics.liveRegion
+import androidx.compose.ui.semantics.semantics
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.input.KeyboardType
 import androidx.compose.ui.tooling.preview.Preview
@@ -76,6 +79,7 @@ internal fun AuthSignUpScreen(
     isSubmitting: Boolean,
     statusMessage: String?,
     isStatusError: Boolean,
+    isVerificationCodeError: Boolean,
     step: Int,
     onEvent: (AuthSignUpScreenEvent) -> Unit,
     modifier: Modifier = Modifier,
@@ -251,8 +255,13 @@ internal fun AuthSignUpScreen(
                                         onEvent(AuthSignUpScreenEvent.VerificationCodeChanged(code))
                                     },
                                     enabled = !isSubmitting && !isSendingEmailCode && emailCodeRemainingSeconds > 0,
+                                    errorDescription = statusMessage.takeIf { isVerificationCodeError },
+                                )
+                                SignUpErrorMessage(
+                                    isError = isStatusError,
+                                    message = statusMessage,
+                                    isLiveRegion = isVerificationCodeError,
                                 )
-                                SignUpErrorMessage(isStatusError, statusMessage)
                             }
 
                             if (step == SIGN_UP_CODE_STEP) {
@@ -261,16 +270,26 @@ internal fun AuthSignUpScreen(
                                     horizontalArrangement = Arrangement.SpaceBetween,
                                     verticalAlignment = Alignment.CenterVertically,
                                 ) {
-                                    Text(
-                                        text =
-                                            stringResource(
-                                                R.string.auth_signup_code_remaining_time,
-                                                emailCodeRemainingSeconds / SECONDS_PER_MINUTE,
-                                                emailCodeRemainingSeconds % SECONDS_PER_MINUTE,
-                                            ),
-                                        color = MaterialTheme.extraColors.secondaryText,
-                                        style = MaterialTheme.typography.bodySmall,
-                                    )
+                                    Row(
+                                        horizontalArrangement = Arrangement.spacedBy(4.dp),
+                                        verticalAlignment = Alignment.CenterVertically,
+                                    ) {
+                                        Text(
+                                            text = stringResource(R.string.auth_signup_code_remaining_time_label),
+                                            color = MaterialTheme.extraColors.secondaryText,
+                                            style = MaterialTheme.typography.bodySmall,
+                                        )
+                                        Text(
+                                            text =
+                                                stringResource(
+                                                    R.string.auth_signup_code_remaining_time_value,
+                                                    emailCodeRemainingSeconds / SECONDS_PER_MINUTE,
+                                                    emailCodeRemainingSeconds % SECONDS_PER_MINUTE,
+                                                ),
+                                            color = MaterialTheme.colorScheme.primary,
+                                            style = MaterialTheme.typography.bodySmall,
+                                        )
+                                    }
                                     TextButton(
                                         onClick = { onEvent(AuthSignUpScreenEvent.RequestEmailCodeClicked) },
                                         enabled =
@@ -459,11 +478,23 @@ internal fun AuthSignUpScreen(
 private fun SignUpErrorMessage(
     isError: Boolean,
     message: String?,
+    isLiveRegion: Boolean = false,
 ) {
     if (isError && message != null) {
         Text(
             text = message,
-            modifier = Modifier.padding(top = HeartGuardSpacing.AuthErrorMessageGap),
+            modifier =
+                Modifier
+                    .padding(top = HeartGuardSpacing.AuthErrorMessageGap)
+                    .then(
+                        if (isLiveRegion) {
+                            Modifier.semantics {
+                                liveRegion = LiveRegionMode.Polite
+                            }
+                        } else {
+                            Modifier
+                        },
+                    ),
             color = MaterialTheme.colorScheme.error,
             style = MaterialTheme.typography.bodySmall,
         )
@@ -556,6 +587,7 @@ private fun AuthSignUpScreenPreview() {
             isSubmitting = false,
             statusMessage = null,
             isStatusError = false,
+            isVerificationCodeError = false,
             step = SIGN_UP_EMAIL_STEP,
             onEvent = {},
         )
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 02f865cf..43861bbf 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -36,7 +36,8 @@
     <string name="auth_signup_resend_code_action">인증번호 다시 받기</string>
     <string name="auth_signup_resend_code">재요청</string>
     <string name="auth_signup_resend_wait">%1$d초</string>
-    <string name="auth_signup_code_remaining_time">남은 시간 %1$02d:%2$02d</string>
+    <string name="auth_signup_code_remaining_time_label">남은 시간</string>
+    <string name="auth_signup_code_remaining_time_value">%1$02d:%2$02d</string>
     <string name="auth_signup_code_accessibility">인증번호 입력</string>
     <string name="auth_signup_code_digit_count">%1$d자리 입력됨</string>
     <string name="auth_signup_email_verified">인증 완료</string>
@@ -53,7 +54,8 @@
     <string name="auth_signup_code_required">먼저 이메일 인증코드를 받아주세요.</string>
     <string name="auth_signup_form_error">입력한 정보를 확인해주세요.</string>
     <string name="auth_signup_registration_error">가입에 실패했습니다. 코드 만료·이메일 중복 여부를 확인해주세요.</string>
-    <string name="auth_signup_invalid_code_error">인증코드가 올바르지 않거나 만료되었습니다. 코드를 다시 확인해주세요.</string>
+    <string name="auth_signup_invalid_code_error">인증번호가 올바르지 않아요. 다시 확인해주세요.</string>
+    <string name="auth_signup_expired_code_error">인증번호가 만료되었어요. 새 인증번호를 받아주세요.</string>
     <string name="auth_signup_account_not_ready_error">회사 계정 설정이 완료되지 않았습니다. 관리자에게 문의해주세요.</string>
     <string name="auth_signup_app_login">로그인</string>
     <string name="auth_signup_password_hint">8자 이상 입력해주세요</string>
diff --git a/docs/PRODUCT_BRIEF.md b/docs/PRODUCT_BRIEF.md
index bbf79e31..932897e3 100644
--- a/docs/PRODUCT_BRIEF.md
+++ b/docs/PRODUCT_BRIEF.md
@@ -20,6 +20,15 @@
 - 포기할 수 있는 것: Coil 메모리 사용량은 최대한 낮게 유지하고, 서명 URL을 `expiresAt`까지 세션 메모리에서 재사용하며, 다른 기기의 사진 변경은 URL 만료 전까지 늦게 반영될 수 있음 (출처: 사용자 확인 답변, 2026-11-05)
 - 이렇게 한 이유: 이미지 지연을 줄이려는 목표에 맞추면서 메모리 사용을 아끼기 위해 세션 URL 캐시를 선택함 (출처: 사용자 요청 및 확인 답변, 2026-11-05)
 
+## 회원가입 인증번호 오류 표시
+
+- 마지막 확인: 2026-11-07
+- 핵심 사용자: 폭염 현장 작업자 (출처: `README.md`의 개요, 2026-11-06 확인)
+- 해결할 문제: 인증번호가 틀렸을 때 입력 오류를 화면에서 즉시 알아보기 어려움 (출처: 사용자 요청 및 제공 스크린샷, 2026-11-06)
+- 가장 중요한 점: 입력칸 오류 테두리와 오류 문구로 불일치를 바로 인지하게 함 (출처: 사용자 답변, 2026-11-06)
+- 허용할 절충: 현재 앱/API 범위에서 처리하고, 서버 계약이 필요한 남은 시도 횟수는 표시하지 않음 (출처: 사용자 확인 답변, 2026-11-06)
+- 이렇게 한 이유: 서버 변경 없이 인증 실패 피드백을 즉시 알아볼 수 있게 하려는 사용자 선택 (출처: 사용자 답변, 2026-11-06)
+
 ## 프로필 사진 변경 시트 제목 간격
 
 - 마지막 확인: 2026-11-06
@@ -49,6 +58,7 @@
 
 ## 변경 이력
 - 2026-11-06: 홈 위치 기반 날씨 — coarse 위치 권한 동의 후 현재 좌표를 사용하고, 실패 시 기존 팀 날씨 또는 수동 입력으로 대체.
+- 2026-11-06: 회원가입 인증번호 오류 표시 — 불일치·재입력·만료 상태를 구분하고 입력 오류 의미를 보조기술에 전달.
 - 2026-11-05: 프로필 이미지 로딩 최적화 — 사용자 목표와 승인한 세션 캐시 절충을 반영.
 - 2026-11-06: 프로필 사진 변경 시트 제목 간격 — 제목 위쪽 여백을 약 5.dp 늘림.
 - 2026-11-06: 로그인·회원가입 인증 버튼 너비 — 입력 영역과 정렬하고 기존 반응형 여백을 유지.