To facilitate fastening that can adjust the relative positions of connecting members and make disposal and recycling possible by providing a second flange at an intermediate part of a machine screw member.

This fastening rivet 10 is formed of a machine screw member 16 provided with a fitting head 12 at one end part and a first flange 14 at the other end part, and a second flange 18 is provided at an intermediate part of the machine screw member 16. A circumferential groove 20 for forming the second flange 18 is formed at a large diameter side shank 16a in a step part 17 of a shank, and a cylindrical hole 22 for forming the first flange 14 is formed at a tip part of a small diameter side shank 16b. The second flange 18 and the first flange 14 are thereby fittingly locked, and the fitting head 12 and the second flange 18 can slidably be fitted to a guide groove 22a of a second plate member 22. In this case, a first plate member 20 can be formed movably in relation to the second plate member 22.