To provide a control unit of a brushless motor which enables stable starting and transferring from forced synchronous operation to stationary sensorless operation without causing step-out interrupting rotation, by applying a forced synchronous signal corresponding to a load of the motor.

This control unit of the brushless motor is equipped with a comparing means for comparing a voltage of each of the terminals of a plurality of stator windings with a reference voltage, a driving circuit which is connected with each of the terminals of the windings and forms a current applied to each of the windings, and a logic operation means outputting a current flow timing signal to the driving circuit. The logic operation means has periodic data of a plurality of forced synchronous signals which are set corresponding to loads different in every starting.