PURPOSE: To prevent movement of a rotor in a direction of a rotary shaft, to reduce sound, vibration and to obtain a smooth rotation by eliminating an exciting force difference at the time of starting or finishing exciting of phases in a stepping motor having even number of phases of exciting coils around the rotor.

CONSTITUTION: In order to drive a stepping motor, excitation of an exciting coil 9 of a phase A during exciting is once interrupted, excitation of an exciting coil 7 of a phase B is started after a time β, the coil 9 of the phase A is reexcited, and when the excitation of the coil 9 of the phase A is finished, excitation of the coil 7 of the phase B is once interrupted. This excitation is executed in next phase, sequentially repeated to continuously rotate a rotor 2. Incidentally, the β is a maximum time in which the rotor 2 cannot mechanically follow up. With such excitation, a difference of exciting forces at the time of switching the phase to be excited is eliminated, and hence movement of the rotor 2 in a lateral direction is obviated, and noise, vibration can be reduced.