A carbon brush is provided that improves motor efficiency and achieves a longer service life. A carbon brush (1) to be pressed against an electrically-conductive rotor (2) is characterized by containing mesocarbon powder and an aggregate material containing carbon as at least one component thereof. It is preferable that the mesocarbon powder have a substantially spherical shape, and it is also preferable that the mesocarbon powder has been subjected to a preheating treatment. In addition, it is preferable that the temperature of the preheating treatment be from 500°C to 700°C.