To provide a method to dismount a punch rivet mounted to a working piece without damaging the working piece.

In a method to dismount the punch rivet in which an upper die side to drive a punch rivet and a lower die side facing it to bite-in to a working piece are arranged, further peripheral biting-in edges are respectively arranged to the lower die side and the upper die side, a pin is arranged at a state an end face of the pin is arranged on the upper side die side biting-in edge, energy is supplied through the pin, a contact region between the pin and the upper die side biting-in edge 10 is heated up to a melting temperature of the region, after the contact region is cooled, the pin is pulled out against the pressure of a member abutted on the working piece, the punch rive pulled out from the working piece during this process is pulled out.