diff --git a/ChangeLog b/ChangeLog
index 5a92c53db4..aa7578312c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon May 23 15:52:07 2016  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* ext/bigdecimal/bigdecimal.c (isfinite): isfinite does not always
+	  exist.  fixed build error on Windows itroduced at r55123.
+
 Mon May 23 13:19:41 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* include/ruby/ruby.h (rb_scan_args0): make compile error if the
diff --git a/ext/bigdecimal/bigdecimal.c b/ext/bigdecimal/bigdecimal.c
index 3ccad9a508..1354242b0b 100644
--- a/ext/bigdecimal/bigdecimal.c
+++ b/ext/bigdecimal/bigdecimal.c
@@ -30,6 +30,10 @@
 #include <ieeefp.h>
 #endif
 
+#if !defined(HAVE_ISFINITE) && defined(HAVE_FINITE)
+# define isfinite(x) finite(x)
+#endif
+
 /* #define ENABLE_NUMERIC_STRING */
 
 #define MUL_OVERFLOW_SIGNED_INTEGER_P(a, b, min, max) ( \