diff --git a/ChangeLog b/ChangeLog
index 44f72ced7d..a8f2f536d8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Apr 27 12:54:35 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* numeric.c (int_pow): rb_big_pow() may return other than Bignum.
+
 Fri Apr 27 01:51:50 2007  Koichi Sasada  <ko1@atdot.net>
 
 	* compile.c: support multiple splat (e.g, [a, *b, *c, e, *f]).
diff --git a/numeric.c b/numeric.c
index 86728f2063..1425348a95 100644
--- a/numeric.c
+++ b/numeric.c
@@ -2272,9 +2272,11 @@ int_pow(long x, unsigned long y)
 	while (y % 2 == 0) {
 	    long x2 = x * x;
 	    if (x2 < x || !POSFIXABLE(x2)) {
+		VALUE v;
 	      bignum:
-		return rb_big_mul(rb_big_pow(rb_int2big(x), LONG2NUM(y)),
-				  rb_int2big(neg ? -z : z));
+		v = rb_big_pow(rb_int2big(neg ? -x : x), LONG2NUM(y));
+		if (z != 1) v = rb_big_mul(rb_int2big(z), v);
+		return v;
 	    }
 	    x = x2;
 	    y >>= 1;