Abstract: A power conversion device is applicable to a power supply system including a first battery and a second battery having a rated voltage different from a rated voltage of the first battery. The power conversion device includes a charging circuit configured to convert AC power input from an AC power supply into DC power and charge the first battery with the DC power, a voltage converter configured to convert a power supply voltage of the first battery and outputs the converted voltage to the second battery, and an interrupting unit configured to be capable of interrupting a supply of the DC power to the voltage converter during charging of the first battery by the charging circuit.