PURPOSE: To dispense with relief motion in a gear blank headstock, by leaving generating rotative motion stopped in dwell at a section ranging from what a pinion cutter starts shaping a gear blank to what it returns to its original position, which cuts a gear by means of reciprocating linear motion or reciprocating screw motion.

CONSTITUTION: In a gear shaping process by means of intermittent generating motion, since a center distance is constant, a center distance variation A in illustration remains in zero as shown in a center distance variation 33. Generating pitch circle circumferences C and G of a pinion cutter 1 and a gear blank 2 perform generating rotative motion intermittently as shown in points 27W28 and 31W32 whiles ranging from a point 17 where the pinion cutter 1 passes through tooth width B of the gear blank 2 at its return stroke to a point 19 where it starts the next cutting by way of a stroke uppermost end 18. And, a section ranging from a cutting start point 13 of the pinion cutter 1 to return strokes 16W17 by way of a stroke lowermost end 15 of a cutting end point 14 is made to leave the generating rotation stopped in dwell. Length, making the pitch circle circumference C of the pinion cutter 1 shift to points 25W26 and 27W28, is of generating feed per stroke.