PURPOSE: To provide accurately positioning function and high speed rotatability, to extend a range of fine position regulating after stopping and to reduce current consumption at the time of stopping by advancing the phase of a position signal obtained by a noncontact sensor by a second phase advancer, and energizing a coil by the phase-advanced signal.

CONSTITUTION: A noncontact sensor 5 detects the position of a pole tooth of a rotor 7. When an interval of external pulse commands is long, the phase advancing coefficient of a second phase advancer 16 and the value of amplification factor of a processor 14 are altered to vary the slope of a torque distribution near a positioning point, thereby reducing a positioning error against disturbance. If an arbitrary command voltage is applied from a fine position regulating input terminal 19, an amplitude command position signal is phase-advanced by the advancer 16, and the stopping unit of the rotor 7 can be continuously converted according to the value. On the other hand, if an interval of stepping commands is shortened, the output voltage of an F/V converter 15 is increased to become a command of the advancer 16, and the phase advancing amount of a sensor signal becomes larger than that before.