diff --git a/ChangeLog b/ChangeLog
index e9dd7f1421..54c3011ce0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Oct  6 09:19:21 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* io.c (fptr_finalize): use dedicated macro RB_INTEGER_TYPE_P.
+
 Wed Oct  5 18:02:44 2016  SHIBATA Hiroshi  <hsbt@ruby-lang.org>
 
 	* lib/net/http/response.rb: Improve document readability.
diff --git a/io.c b/io.c
index e50d0d07a0..e9ff6f5ff9 100644
--- a/io.c
+++ b/io.c
@@ -4292,14 +4292,10 @@ fptr_finalize(rb_io_t *fptr, int noraise)
     }
 
     if (!NIL_P(err) && !noraise) {
-        switch (TYPE(err)) {
-          case T_FIXNUM:
-          case T_BIGNUM:
+	if (RB_INTEGER_TYPE_P(err))
 	    rb_syserr_fail_path(NUM2INT(err), fptr->pathv);
-
-          default:
-            rb_exc_raise(err);
-        }
+	else
+	    rb_exc_raise(err);
     }
     free_io_buffer(&fptr->rbuf);
     free_io_buffer(&fptr->wbuf);