diff --git a/ChangeLog b/ChangeLog
index 7f12e0ac81..fa0c3769ed 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Jun 14 00:14:29 2013  Tanaka Akira  <akr@fsij.org>
+
+	* bignum.c (bigdivrem): Zero test condition simplified.
+
 Thu Jun 13 23:43:11 2013  Zachary Scott  <zachary@zacharyscott.net>
 
 	* ext/bigdecimal/*: improve documentation, nodoc samples with @mrkn
diff --git a/bignum.c b/bignum.c
index a02f4c4d99..cada8d0658 100644
--- a/bignum.c
+++ b/bignum.c
@@ -3762,11 +3762,14 @@ bigdivrem(VALUE x, VALUE y, volatile VALUE *divp, volatile VALUE *modp)
     BDIGIT_DBL t2;
     BDIGIT dd, q;
 
-    if (BIGZEROP(y)) rb_num_zerodiv();
-    xds = BDIGITS(x);
     yds = BDIGITS(y);
+    while (0 < ny && !yds[ny-1]) ny--;
+    if (ny == 0)
+        rb_num_zerodiv();
+
+    xds = BDIGITS(x);
     while (0 < nx && !xds[nx-1]) nx--;
-    while (!yds[ny-1]) ny--;
+
     if (nx < ny || (nx == ny && xds[nx - 1] < yds[ny - 1])) {
 	if (divp) *divp = rb_int2big(0);
 	if (modp) *modp = x;