diff --git a/src/main/kotlin/com/easternkite/remain/features/fortune/FortuneRoute.kt b/src/main/kotlin/com/easternkite/remain/features/fortune/FortuneRoute.kt
index 1628f8e..8fd6c1d 100644
--- a/src/main/kotlin/com/easternkite/remain/features/fortune/FortuneRoute.kt
+++ b/src/main/kotlin/com/easternkite/remain/features/fortune/FortuneRoute.kt
@@ -61,26 +61,25 @@ fun Application.fortuneRoute() {
                     }
                 )
             )
-            val birth = body
-                .text
-                .takeIf { it.length == 6 }
-                ?.takeIf { it.matches("[0-9]+".toRegex()) }
-                ?: run {
-                    val errorResponse = DrResponse(
-                        text = "${HttpStatusCode.BadRequest} - 생년월일은 숫자로 이루어진 6자리여야 합니다.",
-                        responseType = "ephemeral" // 작성자한테만 표시
-                    )
+            val birth = body.text
+            if (!validateBirth(birth)) {
+                val errorResponse = DrResponse(
+                    text = "${HttpStatusCode.BadRequest} - 생년월일은 숫자로 이루어진 6자리여야 합니다.",
+                    responseType = "ephemeral" // 작성자한테만 표시
+                )
+
+                call.respondText(
+                    text = Json.encodeToString(errorResponse),
+                    contentType = ContentType.Application.Json
+                )
+                return@post
+            }
 
-                    call.respondText(
-                        text = Json.encodeToString(errorResponse),
-                        contentType = ContentType.Application.Json
-                    )
-                    return@post
-                }
             val userTag = DoorayTag.create(
                 tenantId = body.tenantId,
                 userId = body.userId
             )
+
             val response = chat.sendMessage("생년월일 : ${birth}, 기준 날짜 : $currentTimeFormatted")
             val fortuneJson = response.text?.let { text ->
                 println(text)
@@ -126,6 +125,20 @@ fun Application.fortuneRoute() {
     }
 }
 
+fun validateBirth(birth: String): Boolean {
+    if (birth.length != 6) return false
+
+    val (_, month, day) = runCatching {
+        birth.chunked(2) { it.toString().toInt() }
+    }.getOrNull() ?: return false
+
+    val isPossibleMonth = month in 1..12
+    val isPossibleDay = day in 1 .. 31
+
+    return isPossibleMonth && isPossibleDay
+}
+
+
 data class FortuneField(
     val title: String,
     val section: Section,
diff --git a/src/test/kotlin/com/easternkite/remain/features/fortune/FortuneRouteKtTest.kt b/src/test/kotlin/com/easternkite/remain/features/fortune/FortuneRouteKtTest.kt
new file mode 100644
index 0000000..0d9164b
--- /dev/null
+++ b/src/test/kotlin/com/easternkite/remain/features/fortune/FortuneRouteKtTest.kt
@@ -0,0 +1,48 @@
+package com.easternkite.remain.features.fortune
+
+import org.junit.Test
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+class ValidateBirthTest {
+
+    @Test
+    fun `생년월일이 6자 이상일 때 false`() {
+        assertFalse(validateBirth("9709088"))
+    }
+
+    @Test
+    fun `생년월일중, 태어난 달이 12월을 초과할 때 false`() {
+        assertFalse(validateBirth("971308"))
+    }
+
+    @Test
+    fun `생년월일중, 태어난 일이 31일을 초과할 때 false`() {
+        assertFalse(validateBirth("970132"))
+    }
+
+    @Test
+    fun `태어난 월, 일이 0일 때 false`() {
+        assertFalse(validateBirth("000000"))
+    }
+
+    @Test
+    fun `태어난 월, 일이 99일 때 false`() {
+        assertFalse(validateBirth("999999"))
+    }
+
+    @Test
+    fun `99년 12월 31일 경계값 true`() {
+        assertTrue(validateBirth("991231"))
+    }
+
+    @Test
+    fun `00년 01월 01일 경계값 true`() {
+        assertTrue(validateBirth("000101"))
+    }
+
+    @Test
+    fun `한글, 특수문자 들어가 있는 경우 false`() {
+        assertFalse(validateBirth("__--얍얍"))
+    }
+}
\ No newline at end of file