Method of manufacturing a gear

A method of manufacturing a gear having external teeth on an outer circumferential wall surface thereof and internal teeth on an inner circumferential wall surface thereof, comprising the steps of:

• bringing a pressing die and an external tooth machining die toward a workpiece having a through hole, with an internal tooth forming die being inserted in the through hole, the workpiece being supported from below by a support die, and causing the pressing die to abut against the workpiece;
• forming the external teeth on the outer circumferential wall surface of the workpiece by lowering the external tooth machining die while preventing the support die from being lowered under action of damping mechanisms that support the support die from below;
• and
• after the external tooth machining die abuts against the support die, pressing the support die to cause some or all of the damping mechanisms to descend, and pressing the workpiece with the external teeth formed thereon by the pressing die to lower the workpiece along the internal tooth forming die for thereby forming the internal teeth on the inner circumferential wall surface of the workpiece.