Abstract: A brushless D.C. motor wherein one of projected stator poles positioned to be mutually equally spaced in mechanical angle is made sufficiently smaller than the other as partly cut off at circumferentially expanding pole tooth part, the stator poles being respectively polarized depending on controllably varied direction of direct current to coils on the poles by means of a rotor position detecting Hall element which detects the polarity at a predetermined position of the rotor, for allowing the rotor to self-start constantly in one direction with a remarkably increased starting torque.