PURPOSE: To improve the work efficiency, by arranging punches toward the inside circumferential part and the outside circumferential part of a ring-shaped recess face and working the shell of a turbine impeller or the like while rotating and stopping a die, where the shell is fixed, in case of the emboss work for the shell.

CONSTITUTION: A die where a ring-shaped recess face 5 of a shell 1 of a turbine impeller or the like is fixed and supported upward is rotated and stopped intermittently by an index mechanism. Punches 20 supported freely slidably in the punching direction by guides 29 are arranged toward an outside circumferential part 22 and an inside circumferential part 22a of the ring-shaped recess face 5. Cam drivers 36 are extended from a cam holder 56 to parts near respective punches 20, and supports 26 of respective punches 20 are engaged freely slidably with cam drivers 36. Cam drivers 36 fall to project punches 20 in the punching direction, and the outside circumferential part 22 and the inside circumferential part 22a are subjected to the emboss work by punch projecting parts 21.