A motor driver includes a first signal selector and a second signal selector. The first signal selector is used for selecting a signal to be supplied to an energizing unit of driving coils, and selects either one of a normal energizing pattern signal supplied from an energizing signal generator or a signal from the second signal selector based on a signal from an over-current detector. The second signal selector selects either one of a first non-normal energizing pattern signal from a first energizing signal output unit or a second non-normal energizing pattern signal from a second energizing signal output unit based on a signal from a rotary direction detector.