diff --git a/ChangeLog b/ChangeLog
index 65a52edaf3..0e1f1dec32 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sat Apr 16 09:59:40 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* struct.c (struct_make_members_list): extract making member name
+	  list from char* va_list, with creating symbols without
+	  intermediate IDs.
+
 Sat Apr 16 01:33:27 2016  CHIKANAGA Tomoyuki  <nagachika@ruby-lang.org>
 
 	* tool/redmine-backporter.rb: sort revisions.
diff --git a/struct.c b/struct.c
index a2aa708eff..ee63f4e148 100644
--- a/struct.c
+++ b/struct.c
@@ -330,6 +330,20 @@ rb_struct_alloc_noinit(VALUE klass)
     return struct_alloc(klass);
 }
 
+static VALUE
+struct_make_members_list(va_list ar)
+{
+    char *mem;
+    VALUE ary = rb_ary_tmp_new(0);
+
+    while ((mem = va_arg(ar, char*)) != 0) {
+	VALUE sym = rb_sym_intern_ascii_cstr(mem);
+	rb_ary_push(ary, sym);
+    }
+    OBJ_FREEZE_RAW(ary);
+    return ary;
+}
+
 static VALUE
 struct_define_without_accessor(VALUE outer, const char *class_name, VALUE super, rb_alloc_func_t alloc, VALUE members)
 {
@@ -364,15 +378,10 @@ rb_struct_define_without_accessor_under(VALUE outer, const char *class_name, VAL
 {
     va_list ar;
     VALUE members;
-    char *name;
 
-    members = rb_ary_tmp_new(0);
     va_start(ar, alloc);
-    while ((name = va_arg(ar, char*)) != NULL) {
-        rb_ary_push(members, ID2SYM(rb_intern(name)));
-    }
+    members = struct_make_members_list(ar);
     va_end(ar);
-    OBJ_FREEZE_RAW(members);
 
     return struct_define_without_accessor(outer, class_name, super, alloc, members);
 }
@@ -382,15 +391,10 @@ rb_struct_define_without_accessor(const char *class_name, VALUE super, rb_alloc_
 {
     va_list ar;
     VALUE members;
-    char *name;
 
-    members = rb_ary_tmp_new(0);
     va_start(ar, alloc);
-    while ((name = va_arg(ar, char*)) != NULL) {
-        rb_ary_push(members, ID2SYM(rb_intern(name)));
-    }
+    members = struct_make_members_list(ar);
     va_end(ar);
-    OBJ_FREEZE_RAW(members);
 
     return struct_define_without_accessor(0, class_name, super, alloc, members);
 }
@@ -400,17 +404,10 @@ rb_struct_define(const char *name, ...)
 {
     va_list ar;
     VALUE st, ary;
-    char *mem;
-
-    ary = rb_ary_tmp_new(0);
 
     va_start(ar, name);
-    while ((mem = va_arg(ar, char*)) != 0) {
-	ID slot = rb_intern(mem);
-	rb_ary_push(ary, ID2SYM(slot));
-    }
+    ary = struct_make_members_list(ar);
     va_end(ar);
-    OBJ_FREEZE_RAW(ary);
 
     if (!name) st = anonymous_struct(rb_cStruct);
     else st = new_struct(rb_str_new2(name), rb_cStruct);
@@ -422,17 +419,10 @@ rb_struct_define_under(VALUE outer, const char *name, ...)
 {
     va_list ar;
     VALUE ary;
-    char *mem;
-
-    ary = rb_ary_tmp_new(0);
 
     va_start(ar, name);
-    while ((mem = va_arg(ar, char*)) != 0) {
-	ID slot = rb_intern(mem);
-	rb_ary_push(ary, ID2SYM(slot));
-    }
+    ary = struct_make_members_list(ar);
     va_end(ar);
-    OBJ_FREEZE_RAW(ary);
 
     return setup_struct(rb_define_class_under(outer, name, rb_cStruct), ary);
 }