PURPOSE: To enable to cut tapered gears by utilizing a general hobbing machine with its vertical or horizontal column.

CONSTITUTION: A stepped tooth surface having an inclination as a whole or approximately tapered tooth surface is formed by gear cutting by generating process with a gear cutter 11, which is stepwise shifted relative to a gear blank W during cutting. The stepwise relative shift of the gear cutter 11 toward the blank W is performed by the increase or decrease of depth of cut while the cutter is fed parallel to the axis of the blank. Consequently, the gear, the tooth surface of which is tapered, can be cut with a general hobbing machine with its vertical or horizontal column.