PURPOSE: To produce a punch having a smooth surface without machining in the stage of producing the punch for pressing of tray-shaped end plates by the use of a circular steel material as a blank material, by forming the blank material with spinning by a symmetrical rotary forming method using two forming rolls of a flanging machine.

CONSTITUTION: A circular steel plate 1 which is a blank material is subjected beforehand to spinning to a tray shape, whereafter the blank material 1 for a punch is subjected to rotary forming with spinning by a symmetrical rotary forming method using two pieces of forming rolls 2 of a flanging machine. The rolls 2 can be operated with slight forming loci by making best use of the surface roughness of the rolled steel plate; therefore, the punch having a smooth surface without machining is formed.