To provide a method for manufacturing a brush holder capable of surely preventing generation of burrs.

In the method for manufacturing the brush holder 20, in which a front end portion 14b of a quadratic prism type core 14 forming a pair of brush storing portions 22, 22 is made to abut against a columnar body portion 12a of the upper mold 12 of a mold body 11 forming a cylindrical hollow in which a commutator is arranged; and molten resin S is filled in a cavity K formed between the body portion of the upper mold, the core and a lower mold 13 to mold each brush storing portion with the resin, the core is extended, from an opening end 22b of the each brush storing portion, projections 14f, 14e of a peripheral surface 14a of the core forming a groove in the peripheral wall of the each brush storing portion are formed from the rear end 22c of the each brush storing portion in front of the opening end; and after the quadratic prism type front end portion 14b of the core is engaged to a quadratic recessed hole portion 12b formed in the body portion of the upper mold, the pair of brush storing portions are molded with the resin.