To surely caulk and fix the outer diameter end section of a circular plate to the inner periphery section of a clutch outer by restraining the inner diameter end face of the circular plate with a ring-like projection provided on a push metal at the time of caulking on the inner periphery section of the clutch outer.

A circular plate 8 is pressed from the direction of an arrow by a cylindrical push metal 9 to be pressurized and deformed, and caulking force is generated. The push metal 9 is provided with a tapered pressure face 9a and a tapered ring-like projection 9b, and the circular plate 8 is deformed while its inner diameter end section is restrained by the ring-like projection 9b. The deformation of the circular plate 8 to the inner diameter section is regulated, the circular plate 8 is expanded to the outer diameter side that much, the outer diameter end section of the circular plate 8 is forcibly inserted into the inner periphery section of a clutch outer 2 without forming a gap, and it can be surely caulked and fixed. A pedestal 10 is a member for supporting the clutch outer 2 at the time of pressurization by the push metal 9.