To start a brushless motor smoothly without a stepping out in a method wherein the switching of the current application is estimated.

The terminal voltage (induced voltage) of one armature winding of a brushless motor is compared with a reference voltage by a position detector 10 and the detection result (position detection signal) is inputted to a controller 11. The controller 11 detects the position of a rotor 2a in accordance with the inputted position detection signal and switches the current application to the brushless motor 2 in accordance with the position detection. The switching timings of the other phases are estimated in accordance with the position detection and the current applications are switched at those timings. When the brushless motor 2 is started, a position detection operation wherein the current application to the brushless motor 2 is switched in accordance with the position detection and a synchronous operation wherein the current application to the brushless motor 2 is switched when a predetermined time (T and 2T) passes after the current application switching by the position detection are combined to control the rotation.