Patent ID: 7948200

Claim:
A motor drive device that drives a stepping motor having a rotor mounted on a rotating shaft with a capability of making a transition between a plurality of excitation modes, the motor drive device comprising: a motor control unit that drives the stepping motor by controlling the rotor to move to a position corresponding to one of the excitation modes; a stop control unit that controls, when stopping the stepping motor, the rotor to stop at a position to which the rotor is moved by the motor control unit that is common to the plurality of excitation modes after being instructed to stop the rotor; and a stop-excitation-mode storing unit that stores therein an excitation mode corresponding to the position at which the rotor stops, wherein when the stop control unit is instructed to move the rotor to a position corresponding to the excitation mode stored in the stop-excitation-mode storing unit, the stop control unit sends a position flag indicating that the rotor is controlled to move to the position corresponding to the excitation mode stored in the stop-excitation-mode storing unit, and the stop control unit sends a position flag indicating that the rotor is moved to a two-phase position every time controlling the rotor to be moved to the two-phase position, and when controlling the rotor to stop, sends a stop instruction flag instructing a stop of the rotor, determines, after sending the stop instruction flag, a position from which the position flag indicating that the rotor is moved to the two-phase position is sent, to be the position at which the rotor stops, and controls the rotor to stop at the position at which the rotor stops.