To provide a method of manufacturing a brush for a commutator motor which can obtain the brush which can lengthen a lifetime by lowering a wear coefficient and a fraction abrasion loss.

The method of manufacturing the brush for the commutator motor to supply a power to the motor by pushing to a commutator and contacting includes: an agitating step of mixing a graphite, a thermosetting resin, and a carbon nanotube, and agitating the mixture; a dissolving step of dissolving the thermosetting resin to obtain a slurry after the agitating step; an ultrasonic irradiating step of irradiating an ultrasonic wave to the slurry while agitating the slurry obtained according to this dissolving step; a drying step of drying the slurry obtained by the ultrasonic irradiating step and powdering the dried slurry; and a molding step of heating the powder obtained by the drying step while pressurizing the obtained powder and molding into a brush shape.