Abstract: A brushless motor comprises a rotor having multipolar magnets magnetized, a stator coil having a plurality of phases of winding, a rotor position detecting circuit to detect a specified position of the rotor and to output a signal having levels which alternately change in accordance with revolution of the rotor, and a phase changing circuit to output driving signals to the stator coil in accordance with the output of the rotor position detecting circuit, a stop time signal generating circuit to output a drive-stop signal for stopping the actuation of the stator coil for a predetermined time from the time when a level of the output signal of the rotor position detecting circuit is changed, a temperature detecting element to detect the temperature of an object to be cooled, an instruction value generating circuit to output to the stop time signal generating circuit an instruction signal in response to the output of the temperature detecting circuit so as to change the specified time, and an overheat detecting c