An invention allows a stepping motor to be reliably driven to rotate when initializing the driving and allows power consumption of the stepping motor to be reduced. The controller, when initializing the driving (for example, replacing a battery), controls a main drive pulse generator to drive a stepping motor using a main drive pulse having a maximum energy and sets the generation cycle of a pulse down control signal of a pulse down counter for pulsing down the main drive pulse to a first cycle to drive the stepping motor, and when pulsing down the main drive pulse to that having a predetermined energy, changes the generation cycle of the pulse down control signal of the pulse down counter to a second cycle.