PURPOSE: To allow the forming work of either a front side or a rear side of a metal plate and to unnecessitate the change of die attaching to the machine each time when a forming direction is changed.

CONSTITUTION: A punch 9 is attached movably only for a prescribed amount in the direction of the axial line on a punch head 5; and a cylindrical punch guide 15 surrounding the outer circumference of the punch 9 is attached movably only for a prescribed amount in the direction of the axial line. Between the punch head 5 and the punch 9, an urethane rubber 19 is provided; and between the punch head 5 and a punch guide 15, an urethane rubber 21 is provided. A punch fixing member 31 and a punch guide fixing member 33 are provided which selectively inhibit, by making freely insertable respectively between the punch head 5 and the punch 9 and between the punch head 5 and the punch guide 15, that the punch and the punch guide are relatively displaced in the direction mutually approaching the axial line.