To solve the problem that when a cup noodle is cooked, after opening a lid to a specified position, hot water is poured, the lid is returned, and in order to keep the lid under that state, a plate, a pan lid, or a book is placed on the lid as a weight, and therefore, in many cases, those items have to be searched, and inconvenience is felt.

On the mouth of a cup, this simple cap made of a resin is installed. In this case, the simple cap has a gap for which two sheet portions of the thickness of the edge of the cap and the thickness of the lid are totaled is provided by a length of 1/33 to 1/4 of the opening section for pouring hot water with one end of the simple cap made wider. When the lid is returned after pouring hot water over the cup noodle, the simple cap is slid.