In order to provide a drive circuit for a brushless DC motor that operates even with low power, without using a Hall element, etc., and is capable of being conventionally started regardless of the weight of a load or the size of the moment of inertia, the drive circuit is provided with: a two-stage amplification circuit for a transistor (13) and a transistor (14), that switches and amplifies a drive current for a drive coil (11); a detection coil (15) disposed together with the drive coil within the magnetic field of permanent magnets of a rotor and having one end thereof connected to the base of the transistor (14); and diodes connected in series to the other end of the detection coil (15), provided between the transistor (14) base and emitter, and controlling and adjusting the base current of the transistor (14) such that the transistor (14) turns ON when an induced electromotive force generated by the detection coil (15) is in a reverse-direction voltage state and such that the transistor (14) turns OFF when the induced electromotive force of the detection coil (15) is in a forward-direction voltage state.