A multiphase current supplying circuit includes a converter, an intervening circuit, an inverter, a control circuit and a lightning arrester. A power supply system is connected to the converter with the lightning arrester interposed therebetween, and the ac voltage is rectified. The intervening circuit includes a capacitor and a bypass connected in parallel thereto. In the bypass, a diode, a resistor and a capacitor are connected in series, and the direction from an anode to a cathode of the diode corresponds to the direction from a high potential side to a low potential side of the smoothing capacitor.