To keep the restoring force of a clip extending to a long period of time by a method wherein the longitudinal width of a pinching groove is formed to be slightly larger than the longitudinal width of the pinching part of the clip, and when the clip is attached by pinching to a barrel cylinder, the tops and the bottoms of sides being confronted with each other of the pinching part of the clip are brought into contact with an upper internal step and a lower internal step which are confronted with each other of the pinching groove.

At the top of a barrel cylinder 1, a pinching groove 9 is circumferentially formed, and the pinching cylinder part 11 of a clip 1 made of metal is pinched under a press-fitted state. The pinching cylinder part 11 is formed facing forward by bending it from the rear end of the clip 10, and on the back surface, a ring-shaped cut-out part is formed. Then, the longitudinal width Y of the pinching groove 9 is formed to be slightly wider than the width X of the pinching cylinder part 11. In addition, the upper end 11a on the clip main body 13 side of the pinching cylinder 11 is brought into contact with an upper step 9a of the pinching groove 9, and the lower end 11b on the opposide side of the pinching cylinder part 11 is brought into contact with a lower step part 9b of the pinching groove 9. In the meantime, both side surfaces of the main body part 13 of the clip 10 form a side wall part 14 by applying a bending.