A brushless motor driven by a sensorless driving circuit includes a rotating body capable of being rotated about a center axis; a rotor magnet arranged coaxially with the rotating body; a stator disposed opposite the rotor magnet; and at least one coil wound around the stator. The brushless motor is driven according to a signal containing a third harmonic component relative to a fundamental wave component in an induced electromotive force. Further, an amplitude ratio of the third harmonic component to the fundamental wave component in the induced electromotive force generated in the coil preferably is about 1% or higher.