To select the number of bored holes by a machine model in common by moving one of hollow punches or rotation anvils in the axial direction of a first shaft and selecting a paired number of the hollow punches and the rotary anvils involved in the boring operation.

A punch shaft 1 is rotatably but axially immovably supported to a frame body 8 by bearings 2a-2c and a rotary anvil shaft 4 is rotatably but axially immovably supported by bearings 5a-5c. Punches 3-a to 3-e and a drive gear 7 are fixed on the punch shaft 1 and rotary anvils 6-a to 6e and a knob 15 are fixed on the rotary anvil shaft 4 so that a shifter 11 is rotatably but axially immovably attached by a lock ring 12. When a spring 13 is fitted in a groove in the left side of the shifter 11, the rotary anvil shaft 4 is shifted axially in the right side so that hollow punches 3-a, 3-c, 3-e and the rotary anvils 6-a, 6-c, 6-e are opposed to each other. When the spring 13 is fitted in a groove in the right side of the shifter 11, the hollow punches 3-b, 3-d and the rotary anvils 6-b, 6-d are opposed to each other.