diff --git a/examples/Credential/Credential.ino b/examples/Credential/Credential.ino
index ad72598..7b5b6ae 100644
--- a/examples/Credential/Credential.ino
+++ b/examples/Credential/Credential.ino
@@ -15,7 +15,7 @@
 #include <ESP8266WiFi.h>
 #include <ESP8266WebServer.h>
 #include <AutoConnect.h>
-#include <AutoConnectCredentail.h>
+#include <AutoConnectCredential.h>
 #include <PageBuilder.h>
 
 ESP8266WebServer Server;
diff --git a/mkdocs/faq.md b/mkdocs/faq.md
index a5ceb0e..70699a6 100644
--- a/mkdocs/faq.md
+++ b/mkdocs/faq.md
@@ -66,7 +66,7 @@ The correct boot mode for starting the sketch is **(3, x)**.
 
 Make some sketches for erasing the EEPROM area, or some erasing utility is needed. You can prepare the sketch to erase the saved credential with *AutoConnectCredential*. The *AutoConnectCrendential* class provides the access method to the saved credential in EEPROM and library source file is including it.
 
-A class description of AutoConnectCredentail is follows.
+A class description of AutoConnectCredential is follows.
 
 ### Constructor
 
diff --git a/src/AutoConnectCredential.cpp b/src/AutoConnectCredential.cpp
index a8df8a1..40b45d5 100644
--- a/src/AutoConnectCredential.cpp
+++ b/src/AutoConnectCredential.cpp
@@ -1,6 +1,6 @@
 /**
- *	AutoConnectCredentail class implementation.
- *	@file	AutoConnectCredentail.cpp
+ *	AutoConnectCredential class implementation.
+ *	@file	AutoConnectCredential.cpp
  *	@author	hieromon@gmail.com
  *	@version	1.0.0
  *	@date	2018-02-17
diff --git a/src/AutoConnectCredential.h b/src/AutoConnectCredential.h
index 9ed156d..fd4b429 100644
--- a/src/AutoConnectCredential.h
+++ b/src/AutoConnectCredential.h
@@ -7,8 +7,8 @@
  *  @copyright  MIT license.
  */
 
-#ifndef _AUTOCONNECTCREDENTAIL_H_
-#define _AUTOCONNECTCREDENTAIL_H_
+#ifndef _AUTOCONNECTCREDENTIAL_H_
+#define _AUTOCONNECTCREDENTIAL_H_
 
 #if defined(ARDUINO) && ARDUINO >= 100
   #include "arduino.h"
@@ -50,4 +50,4 @@ class AutoConnectCredential {
   uint16_t  _offset;        /**< The offset for the saved area of credentials in EEPROM. */
 };
 
-#endif  // _AUTOCONNECTCREDENTAIL_H_
+#endif  // _AUTOCONNECTCREDENTIAL_H_