diff --git a/ChangeLog b/ChangeLog
index c12c0575c9..9ec6d059b2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,7 @@
-Tue Sep 22 04:56:18 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Tue Sep 22 05:04:08 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/bigdecimal/lib/bigdecimal/{ludcmp,math}.rb: depend on
+	  bigdecimal.
 
 	* ext/bigdecimal/lib/bigdecimal/*.rb: made module functions.
 
diff --git a/ext/bigdecimal/lib/bigdecimal/ludcmp.rb b/ext/bigdecimal/lib/bigdecimal/ludcmp.rb
index 9b2c3d2330..6cbe29b6da 100644
--- a/ext/bigdecimal/lib/bigdecimal/ludcmp.rb
+++ b/ext/bigdecimal/lib/bigdecimal/ludcmp.rb
@@ -1,3 +1,5 @@
+require 'bigdecimal'
+
 #
 # Solves a*x = b for x, using LU decomposition.
 #
diff --git a/ext/bigdecimal/lib/bigdecimal/math.rb b/ext/bigdecimal/lib/bigdecimal/math.rb
index 191884eb12..2771c77b6f 100644
--- a/ext/bigdecimal/lib/bigdecimal/math.rb
+++ b/ext/bigdecimal/lib/bigdecimal/math.rb
@@ -1,3 +1,5 @@
+require 'bigdecimal'
+
 #
 #--
 # Contents: