A stopper storage case (1) has openings (3) formed at one end thereof, each being large enough to allow spring-like engagement portion of the stopper to pass, and has drill blade insertion paths formed at the other end thereof to be open at the top thereof, each being large enough to allow the drill blade to pass. Concave parts (2) are formed extending from the respective opening to the drill blade insertion path and being capable of storing stoppers different in length from each other. A protrusion is formed in each of the concave parts to be engaged in a groove formed in the outer peripheral surface of the stopper, and stopper holding overhangs is formed at the top of each concave part and which is elastic enough not to interfere with insertion of the stopper from above into the concave part and removal of the stopper from inside the concave part to above.
