POWER SUPPLY DEVICE

A power supply device includes a storage battery; a capacitor unit having first and second capacitor; a three phase power converter, connected in parallel with the storage battery, each phase having first to fourth switching elements in series; three connection terminals electrically connectable to a three-phase AC charger; and a control unit, in a case where the three connection terminals and the three-phase AC charger are electrically connected between the first switching elements and the second switching elements for the respective three phases in the three-level inverter, before the storage battery is charged by means of the three-phase AC charger, charging the first capacitor with use of the storage battery and setting voltage of the second capacitor to 0 V.