PURPOSE: To elongate the life of a die by removing the surface case of the die which can not be used, resinking it, performing electric discharge machining for die sinking and regenerating the used die.

CONSTITUTION: The die (work piece W) which can not be used by die wear, cracking, etc., is introduced into the cabinet 31 of a sandblaster 30. Abrasive material 36 with compressed air is jetted from a nozzle 32 to a surface case of the work piece W and the nitrided layer of the work piece W is removed easily. Then, the work piece W is resink by a machine tool such as a milling machine, etc., and if necessary, a resinking plate is attached to the base for the purpose of supplementing the resink height. Then, electric discharge machining for the sinking is performed to the resink surface of the work piece W to regenerate the die. In this way, the life of the die is elongated and the cost per stock for press forming, etc., is reduced.