PURPOSE: To punch continuously an uneven punching plate by providing a downward projection on a punch part for punching the vicinity of a base part of a projecting part of the tip of the advancing rear side of punching part of a material, and providing a recessed groove on a stripper part for a die corresponding to this projection.

CONSTITUTION: When punching a punching plate by using a punching die, a die use stripper 32 having a recessed groove 33 corresponding to a projection 31 descends by a prescribed pressure. After a narrowed part 34 has been made, eve if a slot cutter 24 of a punch depresses a projecting part 21 to the bottom dead center, the projecting part 21 does not execute horizontal permanent shaping to a rear material, and when a slide cam is drawn upward, the projecting part 21 of the tip springs back and bends upward by residual stress remaining in the narrowed part 34. Accordingly, an influence of flapping of a material is eliminated, and a trouble caused by a fact that the projecting part 21 of the tip is caught by a cutter leading edge of a shaft hole, and a minute step difference or gap between the die use stripper and a die is prevented.