Abstract: Disclosed is a motor-driving device capable of protecting an inverter from breakdown. First current-protecting section retains reference voltage value Vref1 as a preset value. If the current to be fed into inverter exceeds value Vref1, first current-protecting section shuts off the output of driver and outputs a first warning to driving-signal generator to shut off generating driving signals. This protects inverter from breakdown. Second current-protection section retains reference voltage value Vref2 that is smaller than value Vref1. If the detected current exceeds value Vref2, second current-protecting section outputs a second warning. Receiving the second warning, driving-signal generator immediately stops generating driving signals; however, it resumes output of driving signals after no longer receiving second warning. The structure above protects inverter from breakdown without frequent stops of brushless motor.