PURPOSE: To enable continuous, simple and efficient production of a cylindrical gear by forming axially a blank material for the gear by a forward extrusion working method using a die having a tooth profile on the inside circumferential surface and forming a tooth part on the outside circumferential of the blank material.

CONSTITUTION: A bar-shaped blank material for a gear having a relatively long size is extruded in an arrow P direction by using a die 5 having an involute tooth profile 6 on the inside circumferential surface to form a tooth part on the outside circumference of the blank material, by which a long-sized gear blank 7 is obtd. Such blank 7 is cut to a prescribed size (l) by a cutter 8 and thereafter the cut blank is subjected to post working such as machining, by which a spur gear is obtd. The cylindrical gear is inexpensively obtd. with the simple and continuous stage suitable for mass production by the above-mentioned method.