diff --git a/ChangeLog b/ChangeLog
index 4f6e6675b7..2acd0c8ff0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Dec 26 15:20:54 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* marshal.c (w_long): append at once by w_nbyte() instead of
+	  appending byte by byte.
+
 Fri Dec 26 15:13:13 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* ext/json/parser/parser.rl (unescape_unicode): check if valid
diff --git a/marshal.c b/marshal.c
index 6a61ae53b4..43886c4daa 100644
--- a/marshal.c
+++ b/marshal.c
@@ -277,7 +277,7 @@ static void
 w_long(long x, struct dump_arg *arg)
 {
     char buf[sizeof(long)+1];
-    int i, len = 0;
+    int i;
 
 #if SIZEOF_LONG > 4
     if (!(RSHIFT(x, 31) == 0 || RSHIFT(x, 31) == -1)) {
@@ -310,10 +310,7 @@ w_long(long x, struct dump_arg *arg)
 	    break;
 	}
     }
-    len = i;
-    for (i=0;i<=len;i++) {
-	w_byte(buf[i], arg);
-    }
+    w_nbyte(buf, i+1, arg);
 }
 
 #ifdef DBL_MANT_DIG