PURPOSE: To eliminate a deteriorate layer which cannot be removed mechanically by eliminating the deteriorated layer by an electrolytic process after reannealing a discharge processed steel part.

CONSTITUTION: A part after a discharge work is reannealed. The temperature and time for reannealing are determined by the sort of steel. An electrolytic process is applied next. For an anode of a subject matter, a matric electrode is put for a cathode, their interval is set at 0.05-0.5mm, and salt water of 10-24% is sent between them, while a DC voltage of 3-20v is supplied between the anode and cathode for electrolysis. A heat process is thus combined with an electrolytic process. A deteriorated layer generated in a discharge processed surface of steel which cannot be removed mechanically can thus be eliminated easily.