diff --git a/ChangeLog b/ChangeLog
index 5cdf1ccb14..73e62c2780 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Nov 23 07:29:24 2010  Tadayoshi Funaba  <tadf@dotrb.org>
+
+	* complex.c, rational.c ({nucomp,nurat}_expt): added a check.
+
 Tue Nov 23 07:27:27 2010  Tadayoshi Funaba  <tadf@dotrb.org>
 
 	* lib/date.rb (daynum): should be private.
diff --git a/complex.c b/complex.c
index 4bc3005cff..58b900b421 100644
--- a/complex.c
+++ b/complex.c
@@ -1,5 +1,5 @@
 /*
-  complex.c: Coded by Tadayoshi Funaba 2008,2009
+  complex.c: Coded by Tadayoshi Funaba 2008-2010
 
   This implementation is based on Keiju Ishitsuka's Complex library
   which is written in ruby.
@@ -824,7 +824,7 @@ f_reciprocal(VALUE x)
 static VALUE
 nucomp_expt(VALUE self, VALUE other)
 {
-    if (k_exact_zero_p(other))
+    if (k_numeric_p(other) && k_exact_zero_p(other))
 	return f_complex_new_bang1(CLASS_OF(self), ONE);
 
     if (k_rational_p(other) && f_one_p(f_denominator(other)))
diff --git a/rational.c b/rational.c
index 9334b14352..2aec3e264a 100644
--- a/rational.c
+++ b/rational.c
@@ -1,5 +1,5 @@
 /*
-  rational.c: Coded by Tadayoshi Funaba 2008,2009
+  rational.c: Coded by Tadayoshi Funaba 2008-2010
 
   This implementation is based on Keiju Ishitsuka's Rational library
   which is written in ruby.
@@ -929,7 +929,7 @@ nurat_fdiv(VALUE self, VALUE other)
 static VALUE
 nurat_expt(VALUE self, VALUE other)
 {
-    if (k_exact_zero_p(other))
+    if (k_numeric_p(other) && k_exact_zero_p(other))
 	return f_rational_new_bang1(CLASS_OF(self), ONE);
 
     if (k_rational_p(other)) {