A clip body 41 comprises: one upper wall 41a that extends in the longitudinal direction of a shaft cylinder 2; and a pair of side walls 41b formed on at least the front side of the upper wall 41a, the pair of side walls 41b projecting from both side parts of the upper wall 41a toward the surface of the shaft cylinder 2 and having inner surfaces facing each other. A grasping part 42 is provided on the reverse side of the clip body 41 and between the pair of side walls 41b, the grasping part 42 having a shape that can be deformed to generate elastic force, and projecting farther toward the surface of the shaft cylinder 2 than the pair of side walls 41b. The surface of the shaft cylinder 2 is provided with a guide groove 23f that extends in the longitudinal direction of the shaft cylinder 2, the guide groove 23f comprising a bottom surface that contacts the grasping part 42, and a pair of side surfaces that limit movement of the grasping part 42 in the lateral direction. A clip base 43 is joined to the rear side of the clip body 41, the pair of side walls 41b do not contact the surface of the shaft cylinder 2, and the grasping part 42 supports the clip body 41 at a height contacting the bottom surface of the guide groove 23f.