diff --git a/aes128.c b/aes128.c
index ce8d169..86cfc60 100644
--- a/aes128.c
+++ b/aes128.c
@@ -3,7 +3,6 @@
  *    (http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf)
  *  Copyright (C) 2015, T.Kurosawa
  */
-#include <stdio.h>
 #include <strings.h>
 #include "aes128.h"