PURPOSE: To improve the vibration accuracy of a disk by pressurizing the leg part of the disk by a die ring and rotary roll.

CONSTITUTION: A disk is arranged on the shape pilot 2 provided on a lower die 1 and the disk is fixed by pinching it with the descent of an upper die 2. A hub hole punch 21 is inserted into a hub hole in succession and it is rectified in the concentric circle to a pitch circle. The rotary roll 35 provided on the circumference of the die advances toward the die and when it comes into contact with the leg part 41 of the disk, the lower die 1 and upper die 20 are also rotated with the disk according to the rotation of the rotary roll 35 by a motor. With further advance of the rotary roll 35 the leg part 41 is pressurized and deformed in order. And it is formed in the necessary shape between the outer peripheral pressing face 34 of a die ring 23 and rotary roll 35. Consequently the wheel of less twists can be obtd.