diff --git a/src/main/java/com/eactive/eai/common/util/MessageUtil.java b/src/main/java/com/eactive/eai/common/util/MessageUtil.java
index fc5c9a9..4304ff1 100644
--- a/src/main/java/com/eactive/eai/common/util/MessageUtil.java
+++ b/src/main/java/com/eactive/eai/common/util/MessageUtil.java
@@ -1,5 +1,25 @@
 package com.eactive.eai.common.util;
 
+import java.io.BufferedInputStream;
+import java.io.UnsupportedEncodingException;
+import java.nio.charset.Charset;
+import java.util.Iterator;
+
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.xpath.XPath;
+import javax.xml.xpath.XPathConstants;
+import javax.xml.xpath.XPathFactory;
+
+import org.apache.commons.lang3.StringUtils;
+import org.apache.tools.ant.filters.StringInputStream;
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+import org.json.simple.JSONValue;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.w3c.dom.Document;
+
 import com.eactive.eai.common.EAIKeys;
 import com.eactive.eai.common.message.MessageType;
 import com.eactive.eai.common.monitor.EAIServiceMonitor;
@@ -10,30 +30,16 @@ import com.eactive.eai.transformer.util.ISO8583DumpUtil;
 import com.ext.eai.common.stdmessage.STDMessageErrorKeys;
 import com.jayway.jsonpath.JsonPath;
 import com.solab.iso8583.IsoMessage;
-import org.apache.commons.lang3.StringUtils;
-import org.apache.tools.ant.filters.StringInputStream;
-import org.json.simple.JSONArray;
-import org.json.simple.JSONObject;
-import org.json.simple.JSONValue;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-import org.w3c.dom.Document;
-
-import javax.xml.parsers.DocumentBuilder;
-import javax.xml.parsers.DocumentBuilderFactory;
-import javax.xml.xpath.XPath;
-import javax.xml.xpath.XPathConstants;
-import javax.xml.xpath.XPathFactory;
-import java.io.BufferedInputStream;
-import java.io.UnsupportedEncodingException;
-import java.nio.charset.Charset;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
 
 public final class MessageUtil {
 	static Logger logger = LoggerFactory.getLogger(MessageUtil.class);
 	
+	public static final String ERROR_MESSAGE_DEFAULT_FORMAT = "{\"error\":{\"code\":\"%s\",\"message\":\"%s\"}}";
+	
+	public static final String ERROR_CODE_AP_ERROR = "E.GW.AP_ERROR";
+	public static final String ERROR_CODE_AUTH_FAIL = "E.GW.AUTH_FAIL";
+	public static final String ERROR_CODE_SERVICE_NOT_FOUND = "E.GW.SERVICE_NOT_FOUND";
+	
 	private MessageUtil() {
 
 	}
@@ -492,12 +498,10 @@ public final class MessageUtil {
 
 	public static String makeErrorMessageByMessageType(String msgType, String msgCharset, String code, String msg,
 			String errorFormat) {
-		if (StringUtils.equals(msgType, MessageType.JSON)) {
-			return makeJsonErrorMessage(code, msg, errorFormat);
-		} else if (StringUtils.equals(msgType, MessageType.XML)) {
+		if (StringUtils.equals(msgType, MessageType.XML)) {
 			return makeXmlErrorMessage(code, msg, msgCharset, errorFormat);
 		} else {
-			return "[errCd]" + code + "[/errCd]" + "[errMsg]" + msg + "[/errMsg]";
+			return makeJsonErrorMessage(code, msg, errorFormat);
 		}
 	}
 
@@ -510,14 +514,17 @@ public final class MessageUtil {
 	}
 
 	public static String makeJsonErrorMessage(String code, String msg, String errorFormat) {
-		if (StringUtils.isNotBlank(errorFormat)) {
-			try {
-				return String.format(errorFormat, code, JSONValue.escape(msg));
-			} catch (Exception e) {
-				logger.error(e.getMessage());
-			}
+		if (StringUtils.isBlank(errorFormat)) {
+			errorFormat = ERROR_MESSAGE_DEFAULT_FORMAT;
+		}
+
+		// errorFormat에 %s가 1개만 있으면 msg만, 2개 이상이면 code, msg 전달
+		int paramCount = StringUtils.countMatches(errorFormat, "%s");
+		if (paramCount == 1) {
+			return String.format(errorFormat, JSONValue.escape(msg));
+		} else {
+			return String.format(errorFormat, code, JSONValue.escape(msg));
 		}
-		return String.format("{\"error\":\"%s\",\"error_description\":\"%s\"}", code, JSONValue.escape(msg));
 	}
 
 	public static String makeXmlErrorMessage(String code, String msg, String charset, String errorFormat) {