A brushless motor according to the present invention is provided with a tubular stator case, a stator core fitted into the stator case, and a rotor rotatably supported via a bearing inside the stator core. The stator core includes a tubular yoke portion and a plurality of split cores which are detachably mounted on the tubular yoke portion. A plurality of commutating-pole teeth which extend radially inward are integrally formed on an inner peripheral surface of the tubular yoke portion at regular intervals in the peripheral direction of the tubular yoke portion; and a root portion of each of the commutating-pole teeth has inclined shoulders which are gradually enlarged radially outward.