To provide a gear finishing device which can shorten the time required for finishing of tooth flank by continuously applying an appropriate stable magnitude machining load to a gear to be machined, and can suppress deformation of tooth profile due to the finishing processing.

The gear 50 to be machined is held in a centerless state by a drive side lapping gear 21 rotating driven by a drive motor 20, a brake side lapping gear 34 for transmitting a driving torque to a brake motor 33, and a guide gear rotatably supported. The drive motor 20 is operated at a predetermined first rotation speed, the brake motor 33 is operated with the second rotation speed lower than the first rotation speed as a target command rotation speed. The brake motor 33 continuously generates a brake torque in a reverse direction with respect to the driving torque applied from the drive motor 20 through both lapping gears 21, 34 and the gear 50 to be finished.