PURPOSE: To greatly suppress impact noise and wear deformation at the time of punching by providing means for fixing a driven side member to a main driving side member by a hydraulic clamp in the state that the hydraulic clamp is moved to a clamping by a hydraulic means for driving the clamp.

CONSTITUTION: The hydraulic clamp 31 is driven to an unclamping side by a means 34 for feeding and discharging the pressure oil for driving the clamp at the time of adjusting a die height (h). A slide 4 is then advanced and retreated by a mechanism 30 for expanding and contracting hydraulic action to adjust the die height (h). The hydraulic clamp 31 is moved to the clamping side by the hydraulic means 34 for driving the clamp to fix the driven side member B to the main driving side member A of the mechanism 30 by the hydraulic clamp 31. The integrated spacing of the mechanism 8 for driving the slide is, therefore, decreased after the adjustment of the die height (h). The impact noise, wear, and deformation to be generated at the time of punching are greatly suppressed by this device.