To prevent the occurrence of a pitch error by individual accumulative errors by integrating this by sandwiching parallel distance pieces in a prescribed thickness between base metals of respective separative wheels, and performing NC cutting on the blade surfaces of the respective wheel base metals by calculating coordinates by successively adding a thickness of the distance pieces.

Distance pieces 10, 11 are sandwiched in a prescribed thickness between base metals 7A, 7B and between base metals 7B, 7C of respective separative grinding wheels to be fixed to a working wheel holder 12. A blade shape of the wheel base metal 7A is cut from the reference surface with the left side surface of the wheel base metal 7A as the reference surface, and a blade shape of the wheel base metal 7B is cut from the apex (b) of a blade of the wheel base metal 7B with NC coordinates as a reference by calculating the NC coordinates of the apex (a) of the wheel base metal 7A. A blade shape of the wheel base metal 7C is also similarly cut.