A power conversion device comprising: an inner coil configured to transmit power by coupling magnetically to an external coil, - an inverter whose AC side is connected to the inner coil and which is configured to perform power conversion bidirectionally between the AC side and a DC side, and - a bidirectional DC/DC converter which comprises an intermediate capacitor which is connected between the bidirectional DC/DC converter and the inverter, is connected to the DC side of the inverter and which is configured to perform power conversion bidirectionally between a DC power source, which is connected to a side which is opposite to the side of the inverter, and the inverter; a controller configured to control the inverter and the bidirectional DC/DC converter; - wherein in power reception operation in which the inner coil receives power from the external coil and transmits power to the DC power source, the bidirectional DC/DC converter comprising a voltage step-up switching device (5b2) performs as a voltage step-up converter in which a voltage step-up operation is performed by turning the voltage step-up switching device (5b2) ON/OFF and a voltage is stepped up so as for power to be transmitted to a side of the DC power source, - wherein when the controller is configured to switch operation from power reception to power transmission where the power reception operation is switched to power transmission operation in which power is transmitted from the DC power source to the inner coil, the power transmission operation is started after control of discharging charges, which are accumulated in the intermediate capacitor, - wherein control of discharging charges is performed by configuring the controller to increase duty ratio of ON of the voltage step-up switching device (5b2) by the time until a voltage of the intermediate capacitor is lowered to be a predetermined value or lower. an inner coil configured to transmit power by coupling magnetically to an external coil, - an inverter whose AC side is connected to the inner coil and which is configured to - an inverter whose AC side is connected to the inner coil and which is configured to perform power conversion bidirectionally between the AC side and a DC side, and - a bidirectional DC/DC converter which comprises an intermediate capacitor which is connected between the bidirectional DC/DC converter and the inverter, is connected to the DC side of the inverter and which is configured to perform power conversion bidirectionally between a DC power source, which is connected to a side which is opposite to the side of the inverter, and the inverter; a controller configured to control the inverter and the bidirectional DC/DC converter; - wherein in power reception operation in which the inner coil receives power from the external coil and transmits power to the DC power source, the bidirectional DC/DC converter comprising a voltage step-up switching device (5b2) performs as a voltage step-up converter in which a voltage step-up operation is performed by turning the voltage step-up switching device (5b2) ON/OFF and a voltage is stepped up so as for power to be transmitted to a side of the DC power source, - wherein when the controller is configured to switch operation from power reception to power transmission where the power reception operation is switched to power transmission operation in which power is transmitted from the DC power source to the inner coil, the power transmission operation is started after control of discharging charges, which are accumulated in the intermediate capacitor, - wherein control of discharging charges is performed by configuring the controller to increase duty ratio of ON of the voltage step-up switching device (5b2) by the time until a voltage of the intermediate capacitor is lowered to be a predetermined value or lower. - a bidirectional DC/DC converter which comprises an intermediate capacitor which is connected between the bidirectional DC/DC converter and the inverter, is connected to the DC side of the inverter and which is configured to perform power conversion bidirectionally between a DC power source, which is connected to a side which is opposite to the side of the inverter, and the inverter; a controller configured to control the inverter and the bidirectional DC/DC converter; - wherein in power reception operation in which the inner coil receives power from the external coil and transmits power to the DC power source, the bidirectional DC/DC converter comprising a voltage step-up switching device (5b2) performs as a voltage step-up converter in which a voltage step-up operation is performed by turning the voltage step-up switching device (5b2) ON/OFF and a voltage is stepped up so as for power to be transmitted to a side of the DC power source, - wherein when the controller is configured to switch operation from power reception to power transmission where the power reception operation is switched to power transmission operation in which power is transmitted from the DC power source to the inner coil, the power transmission operation is started after control of discharging charges, which are accumulated in the intermediate capacitor, - wherein control of discharging charges is performed by configuring the controller to increase duty ratio of ON of the voltage step-up switching device (5b2) by the time until a voltage of the intermediate capacitor is lowered to be a predetermined value or lower.