An n-phase brushless motor device is provided. The device includes a magnet for magnetic pole position detection having a number of poles twice as many as that of a rotor and fixed to a face perpendicular to a rotation axis of the rotor; n main Hall elements arranged opposite to the magnet, for detecting a magnetic pole position of the rotor; n sub Hall elements arranged in such a way as to have an offset in a direction of a periphery with respect to the main Hall elements, for detecting the magnetic pole position; and a control unit for counting “2” according to a change in an output pattern of the main Hall elements, for counting “1” when the output pattern is the same as that of the sub Hall elements at a predetermined timing, and for controlling a rotation of the rotor according to these counted values.