A rivet includes a sleeve, which has a flange, and a core member, which is inserted into the sleeve. The distal end of the sleeve is coupled to a plurality of pivoting pieces via thin hinges. By inserting the core member into the sleeve, each pivoting piece is pushed against the core member to pivot outward, and a laminated member, which is located between the flange and each pivoting piece, is fixed. A projection is arranged on the basal end surface of each pivoting piece. A hook portion is arranged on the head of the core member to project radially outward of the core member. When the core member is inserted into the sleeve, the hook portion of the core member moves past the projection of each pivoting piece in an outwardly pivoted state to fix the pivoting piece.