An inverter device includes gate driving circuits for upper and lower arms of a bridge circuit, a first power supply supplying a power supply voltage to each driving circuit, and a second power supply having a reference potential different from that of the first power supply. The inverter device also includes a first fail-safe circuit having a reference potential common to the first power supply and generating driving commands with respect to the upper and lower arms, and a second fail-safe circuit having a reference potential common to the second power supply and generating driving commands with respect to the upper or lower arm. The lower arm gate driving circuit has two driving command input functions having different reference potentials, one function inputs the driving commands from the first fail-safe circuit, and the other function inputs the driving commands from the second fail-safe circuit.