diff --git a/ChangeLog b/ChangeLog
index 08949acd96..ca38586c19 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Fri Mar 18 01:51:00 2016  Kenta Murata  <mrkn@mrkn.jp>
+
+	* bignum.c (rb_big_even_p, rb_big_odd_p): make them public functions
+	  to be available in other source files.
+
+	* include/ruby/intern.h (rb_big_even_p, rb_big_odd_p): add prototype
+	  declarations.
+
 Fri Mar 18 00:25:56 2016  Tanaka Akira  <akr@fsij.org>
 
 	* enum.c (ary_inject_op): Implement the specialized code for sum of
diff --git a/bignum.c b/bignum.c
index 34c846a8f3..365bd3efc5 100644
--- a/bignum.c
+++ b/bignum.c
@@ -7006,7 +7006,7 @@ rb_big_bit_length(VALUE big)
  *  Returns <code>true</code> if <i>big</i> is an odd number.
  */
 
-static VALUE
+VALUE
 rb_big_odd_p(VALUE num)
 {
     if (BIGNUM_LEN(num) != 0 && BDIGITS(num)[0] & 1) {
@@ -7022,7 +7022,7 @@ rb_big_odd_p(VALUE num)
  *  Returns <code>true</code> if <i>big</i> is an even number.
  */
 
-static VALUE
+VALUE
 rb_big_even_p(VALUE num)
 {
     if (BIGNUM_LEN(num) != 0 && BDIGITS(num)[0] & 1) {
diff --git a/include/ruby/intern.h b/include/ruby/intern.h
index 816bc7e140..a53cfcb691 100644
--- a/include/ruby/intern.h
+++ b/include/ruby/intern.h
@@ -131,6 +131,8 @@ VALUE rb_big_or(VALUE, VALUE);
 VALUE rb_big_xor(VALUE, VALUE);
 VALUE rb_big_lshift(VALUE, VALUE);
 VALUE rb_big_rshift(VALUE, VALUE);
+VALUE rb_big_odd_p(VALUE);
+VALUE rb_big_even_p(VALUE);
 
 /* For rb_integer_pack and rb_integer_unpack: */
 /* "MS" in MSWORD and MSBYTE means "most significant" */