Inverter with detection of welding of relay contacts

An object is to provide an inverter device capable of detecting the welding of a switching device in early stages, and in summary, the inverter device is equipped with a parallel circuit of a charging circuit and a switch connected between a battery and an inverter module, and comprises a capacitor charged from the battery via the charging circuit; a resistor to discharge the capacitor; a serial circuit including resistors to detect a voltage after the switch; and a diode connected between a connection point of the serial circuit including the resistors on a positive line and a connection point of the capacitor, and directed forward to the capacitor side.