The invention discloses a groove broacher for a commutator of a direct current motor and relates to a groove broacher for a mica sheet groove in a commutator of a direct current motor. The groove broacher comprises a rotor spider, a motor, a cutting tool, a vertical adjustment controller and a horizontal adjustment controller, wherein the motor is arranged on a cutting frame; the cutting tool is connected with the motor; the vertical adjustment controller is used for controlling the vertical movement of the cutting frame; and the horizontal adjustment controller is used for controlling the horizontal movement of the cutting frame. The groove broacher is used as a tool special for repairing the direct current motor, so that the maintenance quality and the time limitation of the direct current motor are guaranteed; and the original manual work is changed into mechanical operation, so that the physical labor is greatly reduced, and the market blank is filled.