PURPOSE: To eliminate the need for cooling the casing inside for changing a die and to improve the efficiency in working by suspending an upper die by the piston of the plural power cylinders arranged isometrically and centripetally.

CONSTITUTION: In case of taking out upper and lower dies, a sliding door 10 is opened, a piston group 14 is moved to the cylinder side by a power cylinder group 13 and after releasing the engaging relation of a die holder 12 and the upper die 2, a piston body 5 is descended and the upper and lower dies are taken out by using the jig of a fork lift, etc. In case of changing the lower die only the piston body 5 is descended in the state of suspending the upper die 2 by the piston group 14 and the lower die only is taken out by using the jig of a fork lift, etc. Consequently the necessity of a worker working by coming into a casing is eliminated.