A brush box (23) for a brush-holder, which is useful as a housing for an electric machine brush (25). The brush box (23) comprises a lower portion (56) for guiding the brush, connected to a mounting (60), and an upper portion (58) for guiding the brush, the lower (56) and upper (58) guiding portions being open on the side of a front surface (35) and a rear surface of the brush (25). The lower (56) and upper (58) guiding portions are separated from one another by a space (61) enabling a braid of the brush (25) to pass through.