diff --git a/src/main/java/roomescape/system/auth/infrastructure/jwt/JwtHandler.kt b/src/main/java/roomescape/system/auth/infrastructure/jwt/JwtHandler.kt
index 5b8afc69..4afd8e3e 100644
--- a/src/main/java/roomescape/system/auth/infrastructure/jwt/JwtHandler.kt
+++ b/src/main/java/roomescape/system/auth/infrastructure/jwt/JwtHandler.kt
@@ -1,64 +1,50 @@
-package roomescape.system.auth.infrastructure.jwt;
+package roomescape.system.auth.infrastructure.jwt
 
-import java.util.Date;
-
-import org.springframework.beans.factory.annotation.Value;
-import org.springframework.http.HttpStatus;
-import org.springframework.stereotype.Component;
-
-import io.jsonwebtoken.ExpiredJwtException;
-import io.jsonwebtoken.Jwts;
-import io.jsonwebtoken.MalformedJwtException;
-import io.jsonwebtoken.SignatureAlgorithm;
-import io.jsonwebtoken.SignatureException;
-import io.jsonwebtoken.UnsupportedJwtException;
-import roomescape.system.exception.ErrorType;
-import roomescape.system.exception.RoomEscapeException;
+import io.jsonwebtoken.*
+import org.springframework.beans.factory.annotation.Value
+import org.springframework.http.HttpStatus
+import org.springframework.stereotype.Component
+import roomescape.system.exception.ErrorType
+import roomescape.system.exception.RoomEscapeException
+import java.util.*
 
 @Component
-public class JwtHandler {
+class JwtHandler(
+        @Value("\${security.jwt.token.secret-key}")
+        private val secretKey: String,
 
-	@Value("${security.jwt.token.secret-key}")
-	private String secretKey;
+        @Value("\${security.jwt.token.access.expire-length}")
+        private val accessTokenExpireTime: Long
+) {
+    fun createToken(memberId: Long): String {
+        val date = Date()
+        val accessTokenExpiredAt = Date(date.time + accessTokenExpireTime)
 
-	@Value("${security.jwt.token.access.expire-length}")
-	private long accessTokenExpireTime;
+        return Jwts.builder()
+                .claim("memberId", memberId)
+                .setIssuedAt(date)
+                .setExpiration(accessTokenExpiredAt)
+                .signWith(SignatureAlgorithm.HS256, secretKey.toByteArray())
+                .compact()
+    }
 
-	public TokenDto createToken(Long memberId) {
-		Date date = new Date();
-		Date accessTokenExpiredAt = new Date(date.getTime() + accessTokenExpireTime);
-
-		String accessToken = Jwts.builder()
-			.claim("memberId", memberId)
-			.setIssuedAt(date)
-			.setExpiration(accessTokenExpiredAt)
-			.signWith(SignatureAlgorithm.HS256, secretKey.getBytes())
-			.compact();
-
-		return new TokenDto(accessToken);
-	}
-
-	public Long getMemberIdFromToken(String token) {
-		validateToken(token);
-
-		return Jwts.parser().setSigningKey(secretKey.getBytes()).parseClaimsJws(token)
-			.getBody()
-			.get("memberId", Long.class);
-	}
-
-	public void validateToken(String token) {
-		try {
-			Jwts.parser().setSigningKey(secretKey.getBytes()).parseClaimsJws(token);
-		} catch (ExpiredJwtException e) {
-			throw new RoomEscapeException(ErrorType.EXPIRED_TOKEN, HttpStatus.UNAUTHORIZED);
-		} catch (UnsupportedJwtException e) {
-			throw new RoomEscapeException(ErrorType.UNSUPPORTED_TOKEN, HttpStatus.UNAUTHORIZED);
-		} catch (MalformedJwtException e) {
-			throw new RoomEscapeException(ErrorType.MALFORMED_TOKEN, HttpStatus.UNAUTHORIZED);
-		} catch (SignatureException e) {
-			throw new RoomEscapeException(ErrorType.INVALID_SIGNATURE_TOKEN, HttpStatus.UNAUTHORIZED);
-		} catch (IllegalArgumentException e) {
-			throw new RoomEscapeException(ErrorType.ILLEGAL_TOKEN, HttpStatus.UNAUTHORIZED);
-		}
-	}
+    fun getMemberIdFromToken(token: String?): Long {
+        try {
+            return Jwts.parser()
+                    .setSigningKey(secretKey.toByteArray())
+                    .parseClaimsJws(token)
+                    .getBody()
+                    .get("memberId", Number::class.java)
+                    .toLong()
+        } catch (e: Exception) {
+            when (e) {
+                is ExpiredJwtException -> throw RoomEscapeException(ErrorType.EXPIRED_TOKEN, HttpStatus.UNAUTHORIZED)
+                is UnsupportedJwtException -> throw RoomEscapeException(ErrorType.UNSUPPORTED_TOKEN, HttpStatus.UNAUTHORIZED)
+                is MalformedJwtException -> throw RoomEscapeException(ErrorType.MALFORMED_TOKEN, HttpStatus.UNAUTHORIZED)
+                is SignatureException -> throw RoomEscapeException(ErrorType.INVALID_SIGNATURE_TOKEN, HttpStatus.UNAUTHORIZED)
+                is IllegalArgumentException -> throw RoomEscapeException(ErrorType.INVALID_TOKEN, HttpStatus.UNAUTHORIZED)
+                else -> throw RoomEscapeException(ErrorType.UNEXPECTED_ERROR, HttpStatus.INTERNAL_SERVER_ERROR)
+            }
+        }
+    }
 }