diff --git a/ChangeLog b/ChangeLog
index aa9714ba0e..9b47ac4145 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -18,7 +18,7 @@ Tue Jun  5 13:17:11 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 	  pack.c, re.c, thread.c, thread_win32.ci, vm.c, vm_dump.c: fixed
 	  indentation.
 
-Mon Jun 04 21:15:45 2007  NARUSE, Yui  <naruse@ruby-lang.org>
+Mon Jun  4 21:15:45 2007  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* lib/json.rb, lib/json, ext/json, test/json:
 	  import JSON library.
@@ -26,6 +26,10 @@ Mon Jun 04 21:15:45 2007  NARUSE, Yui  <naruse@ruby-lang.org>
 	* ext/nkf: import nkf.c rev:1.124
 	  Support CP10001.
 
+Mon Jun  4 20:52:58 2007  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* numeric.c (int_round): should not just truncate.
+
 Sat Jun  2 16:48:55 2007  Koichi Sasada  <ko1@atdot.net>
 
 	* cont.c (Fiber#pass): rename to Fiber#yield.  Block parameter
diff --git a/numeric.c b/numeric.c
index 5f9b98e413..ceaba65fee 100644
--- a/numeric.c
+++ b/numeric.c
@@ -2308,22 +2308,6 @@ int_pow(long x, unsigned long y)
     return LONG2NUM(z);
 }
 
-static VALUE
-int_round(int argc, VALUE* argv, VALUE num)
-{
-    VALUE nd;
-    int ndigits;
-
-    if (argc == 0) return num;
-    rb_scan_args(argc, argv, "1", &nd);
-    ndigits = NUM2INT(nd);
-    if (ndigits > 0) {
-	return rb_Float(num);
-    }
-    ndigits = -ndigits;
-    return rb_funcall(num, '-', 1, rb_funcall(num, '%', 1, int_pow(10, ndigits)));
-}
-
 /*
  *  call-seq:
  *    fix ** other         => Numeric
@@ -2911,6 +2895,31 @@ int_dotimes(VALUE num)
   return num;
 }
 
+static VALUE
+int_round(int argc, VALUE* argv, VALUE num)
+{
+    VALUE n, f, h, r;
+    int ndigits;
+
+    if (argc == 0) return num;
+    if (FIXNUM_P(num)) return num_round(argc, argv, num);
+
+    rb_scan_args(argc, argv, "1", &n);
+    ndigits = NUM2INT(n);
+    if (ndigits > 0) {
+	return rb_Float(num);
+    }
+    ndigits = -ndigits;
+    f = int_pow(10, ndigits);
+    h = rb_funcall(f, '/', 1, INT2FIX(2));
+    r = rb_funcall(num, '%', 1, f);
+    n = rb_funcall(num, '-', 1, r);
+    if (!RTEST(rb_funcall(r, '<', 1, h))) {
+	n = rb_funcall(n, '+', 1, f);
+    }
+    return n;
+}
+
 /*
  *  call-seq:
  *     fix.zero?    => true or false