diff --git a/src/main/kotlin/com/fitmate/batchservice/dto/certification/FitCertificationDetailResponseDto.kt b/src/main/kotlin/com/fitmate/batchservice/dto/certification/FitCertificationDetailResponseDto.kt
index 8895d0d..d82433e 100644
--- a/src/main/kotlin/com/fitmate/batchservice/dto/certification/FitCertificationDetailResponseDto.kt
+++ b/src/main/kotlin/com/fitmate/batchservice/dto/certification/FitCertificationDetailResponseDto.kt
@@ -1,6 +1,7 @@
 package com.fitmate.batchservice.dto.certification
 
 import com.fitmate.batchservice.persistence.entity.CertificationStatus
+import com.fitmate.batchservice.utils.DateParseUtils
 import java.time.Instant
 
 data class FitCertificationDetailResponseDto(
@@ -9,6 +10,8 @@ data class FitCertificationDetailResponseDto(
     val userId: Int,
     val certificationStatus: CertificationStatus,
     val state: Boolean,
-    val createdAt: Instant,
-    val voteEndDate: Instant
-)
+    val createdAt: String,
+    val voteEndDate: String
+) {
+    val voteEndDateInstant: Instant = DateParseUtils.stringToInstant(voteEndDate)
+}
diff --git a/src/main/kotlin/com/fitmate/batchservice/dto/certification/FitCertificationResultResponse.kt b/src/main/kotlin/com/fitmate/batchservice/dto/certification/FitCertificationResultResponse.kt
index 6ccb2d2..6b54010 100644
--- a/src/main/kotlin/com/fitmate/batchservice/dto/certification/FitCertificationResultResponse.kt
+++ b/src/main/kotlin/com/fitmate/batchservice/dto/certification/FitCertificationResultResponse.kt
@@ -1,10 +1,13 @@
 package com.fitmate.batchservice.dto.certification
 
 import com.fitmate.batchservice.persistence.entity.CertificationStatus
+import com.fitmate.batchservice.utils.DateParseUtils
 import java.time.Instant
 
 data class FitCertificationResultResponse(
     val fitCertificationId: Long,
     val certificationStatus: CertificationStatus,
-    val createdAt: Instant
-)
\ No newline at end of file
+    private val createdAtInstant: Instant
+) {
+    val createdAt: String = DateParseUtils.instantToString(createdAtInstant)
+}
\ No newline at end of file
diff --git a/src/main/kotlin/com/fitmate/batchservice/dto/penalty/FitPenaltyDetailResponse.kt b/src/main/kotlin/com/fitmate/batchservice/dto/penalty/FitPenaltyDetailResponse.kt
index d2196b0..709c5cd 100644
--- a/src/main/kotlin/com/fitmate/batchservice/dto/penalty/FitPenaltyDetailResponse.kt
+++ b/src/main/kotlin/com/fitmate/batchservice/dto/penalty/FitPenaltyDetailResponse.kt
@@ -1,5 +1,6 @@
 package com.fitmate.batchservice.dto.penalty
 
+import com.fitmate.batchservice.utils.DateParseUtils
 import java.time.Instant
 
 data class FitPenaltyDetailResponse(
@@ -7,5 +8,7 @@ data class FitPenaltyDetailResponse(
     val fitGroupId: Long,
     val userId: Int,
     val amount: Int,
-    val createdAt: Instant
-)
+    private val createdAtInstant: Instant
+) {
+    val createdAt: String = DateParseUtils.instantToString(createdAtInstant)
+}
diff --git a/src/main/kotlin/com/fitmate/batchservice/persistence/entity/FitCertificationForRead.kt b/src/main/kotlin/com/fitmate/batchservice/persistence/entity/FitCertificationForRead.kt
index 8ee4f29..24cb608 100644
--- a/src/main/kotlin/com/fitmate/batchservice/persistence/entity/FitCertificationForRead.kt
+++ b/src/main/kotlin/com/fitmate/batchservice/persistence/entity/FitCertificationForRead.kt
@@ -28,7 +28,7 @@ class FitCertificationForRead private constructor(
         eventPublisher: String
     ) {
         this.fitCertificationId = fitCertificationDetail.fitCertificationId
-        this.certificationEndDate = fitCertificationDetail.voteEndDate
+        this.certificationEndDate = fitCertificationDetail.voteEndDateInstant
         this.certificationStatus = fitCertificationDetail.certificationStatus
         this.fitGroupId = fitCertificationDetail.fitGroupId
         this.userId = fitCertificationDetail.userId
@@ -46,7 +46,7 @@ class FitCertificationForRead private constructor(
                 fitCertificationDetail.fitCertificationId,
                 fitCertificationDetail.fitGroupId,
                 fitCertificationDetail.userId,
-                fitCertificationDetail.voteEndDate,
+                fitCertificationDetail.voteEndDateInstant,
                 fitCertificationDetail.certificationStatus,
                 fitCertificationDetail.state,
                 eventPublisher
diff --git a/src/main/kotlin/com/fitmate/batchservice/utils/DateParseUtils.kt b/src/main/kotlin/com/fitmate/batchservice/utils/DateParseUtils.kt
new file mode 100644
index 0000000..b0e0a0d
--- /dev/null
+++ b/src/main/kotlin/com/fitmate/batchservice/utils/DateParseUtils.kt
@@ -0,0 +1,49 @@
+package com.fitmate.batchservice.utils
+
+import com.fitmate.batchservice.exception.NotExpectResultException
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
+import java.time.DateTimeException
+import java.time.Instant
+import java.time.OffsetDateTime
+import java.time.ZoneId
+import java.time.format.DateTimeFormatter
+
+class DateParseUtils {
+
+    companion object {
+        val logger: Logger = LoggerFactory.getLogger(DateParseUtils::class.java)
+
+        const val DEFAULT_FORMAT = "yyyy-MM-dd HH:mm:ss.SSSSSSXXX"
+
+        fun instantToString(instant: Instant?): String {
+            instant ?: return ""
+
+            val zonedDateTime = instant.atZone(ZoneId.systemDefault())
+
+            val formatter = DateTimeFormatter.ofPattern(DEFAULT_FORMAT)
+
+            val formattedDate = zonedDateTime.format(formatter)
+
+            return formattedDate
+        }
+
+        fun stringToInstant(stringInstantDate: String): Instant {
+            val formatter = DateTimeFormatter.ofPattern(DEFAULT_FORMAT)
+
+            var result: Instant? = null
+
+            try {
+                val offsetDateTime = OffsetDateTime.parse(stringInstantDate, formatter)
+
+                result = offsetDateTime.toInstant()
+            } catch (e: DateTimeException) {
+                logger.error("string to instant parse exception ", e)
+            }
+
+            if (result == null) throw NotExpectResultException("string to instant parse result null")
+
+            return result
+        }
+    }
+}
\ No newline at end of file