PURPOSE: To prevent decrease in yield, deformation of a worked part, etc. by embossing a plate-shaped work prior to slitting or notching and working flat the embossed part after the slitting or notching.

CONSTITUTION: A work is embossed by an embossing punch 61 and a die 57 after working of a pilot hole A and a slitting and joining hole B. The work is thereafter notched by an upper blade 45 and a lower blade 47 and the embossed part N is crushed by a flat die 65 and a die 67. The work is further worked with a slit E by a slitting punch 39 and a die 43. The decrease in the yield of the work is prevented by such mechanism. Generation of burr scrup and indentation of the product are prevented by elongating the work.