diff --git a/src/macro.c b/src/macro.c
index d83cad73..380d66d4 100644
--- a/src/macro.c
+++ b/src/macro.c
@@ -2,8 +2,6 @@
  * See Copyright Notice in picrin.h
  */
 
-#include <string.h>
-
 #include "picrin.h"
 #include "picrin/pair.h"
 #include "picrin/proc.h"