A power supply device for vehicle, comprising: an electric load that operates at a predetermined low voltage; a high-voltage power supply that obtains a high-voltage DC power supply by connecting in series a plurality of power storage elements constituting each node that supplies said predetermined low voltage; a high-voltage load device connected to the high-voltage power supply via a wire harness; a plurality of switch means provided corresponding to each node that supplies the predetermined low voltage to the electric load; a control means, wherein the control means supplies a voltage by turning on the switch means for supplying a voltage from at least one node and turning off the switch means for supplying a voltage from another node, after setting a dead time period to turn off all switch means once, by sequentially repeating the control of turning on the switch means of the node that supplies the voltage next and turning off the switch means that supplies the voltage from the other node, the voltage is supplied from all the storage elements; a cutoff means for cutting off an electric circuit between the high-voltage power supply and the high-voltage load device; and a leakage detection means that detects a leakage current between the high voltage power supply and a ground potential and sends a signal to said control means, wherein the control means determines the signal transmitted from the leakage detection means during the dead time period when the plurality of switching means are all off, and when the leakage current is equal to or higher than a predetermined current, the cutoff means are kept off for a predetermined period of time. an electric load that operates at a predetermined low voltage; a high-voltage power supply that obtains a high-voltage DC power supply by connecting in series a plurality of power storage elements constituting each node that supplies said predetermined low voltage; a high-voltage load device connected to the high-voltage power supply via a wire harness; a plurality of switch means provided corresponding to each node that supplies the predetermined low voltage to the electric load; a control means, wherein the control means supplies a voltage by turning on the switch means for supplying a voltage from at least one node and turning off the switch means for supplying a voltage from another node, after setting a dead time period to turn off all switch means once, by sequentially repeating the control of turning on the switch means of the node that supplies the voltage next and turning off the switch means that supplies the voltage from the other node, the voltage is supplied from all the storage elements; a cutoff means for cutting off an electric circuit between the high-voltage power supply and the high-voltage load device; and a leakage detection means that detects a leakage current between the high voltage power supply and a ground potential and sends a signal to said control means, wherein the control means determines the signal transmitted from the leakage detection means during the dead time period when the plurality of switching means are all off, and when the leakage current is equal to or higher than a predetermined current, the cutoff means are kept off for a predetermined period of time.