To simplify the structure, and to reduce the manufacturing time and the manufacturing cost by fitting a balance weight and a slide between an upper frame and a lower frame to a guide rod part provided on a tie rod in a vertically movable manner.

When a drive gear 9 is driven by a servo motor to turn main gears 13A, 13B, a first cam 14A and a second cam 14B are turned through shafts 12A, 12B. A balance weight 5 and a slide 6 are relatively and vertically moved by turning the first cam 14A and the second cam 14B through first stands 15A, 15A, 15B, 15B having cam followers 17A, 17A, 17B, 17B to hold the first cam 14A and the second cam 14B and second stands 16A, 16B. A work is pressed by a die provided between a lower frame 2B and the slide 6 while dynamically balanced.