To improve the vertical positioning accuracy of a die even when a vertical stay member is long by providing a straight motion mechanism rail on the single vertical stay member, engaging a plurality of exclusive nuts with the straight motion mechanism, fitting each arm for exchanging the die to each exclusive nut, and independently control the drive of each nut by individual motors.

A rail 16 of a high-speed straight motion mechanism is fitted to a vertical stay 7. The rail 16 of the high-speed straight motion mechanism has a plurality of continuous rack teeth 16a. A plurality of high-speed straight motion mechanism nuts 17 are engaged with the rail 16 of the high-speed straight motion mechanism and P/D changer arms 8, 9 are respectively fitted to the high-speed straight motion mechanism nuts 17. An AC servo motor 18 is fitted to each high-speed straight motion mechanism nut 17 to control the rotation of the AC servo motor 18, and the position of a punch P and a die D is rapidly, independently and correctly positioned through the P/D changer arms 8, 9.