diff --git a/ChangeLog b/ChangeLog
index 73b959ba4a..9605862834 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Mon May  5 17:26:09 2014  Tadayoshi Funaba  <tadf@dotrb.org>
+
+	* math.c (rb_math_sqrt): omitted exporting an unused function,
+	  anyway.
+	* internal.h: follows the above change.
+
 Mon May  5 11:44:03 2014  Tanaka Akira  <akr@fsij.org>
 
 	* lib/time.rb (Time.strptime): Raise ArgumentError if Date._strptime
diff --git a/internal.h b/internal.h
index b02f926feb..5a89da41d6 100644
--- a/internal.h
+++ b/internal.h
@@ -635,7 +635,9 @@ VALUE rb_math_hypot(VALUE, VALUE);
 VALUE rb_math_log(int argc, VALUE *argv);
 VALUE rb_math_sin(VALUE);
 VALUE rb_math_sinh(VALUE);
+#if 0
 VALUE rb_math_sqrt(VALUE);
+#endif
 
 /* newline.c */
 void Init_newline(void);
diff --git a/math.c b/math.c
index e1fa74fd33..8911de1360 100644
--- a/math.c
+++ b/math.c
@@ -926,7 +926,9 @@ rb_math_log(int argc, VALUE *argv)
 
 exp1(sin)
 exp1(sinh)
+#if 0
 exp1(sqrt)
+#endif
 
 
 /*