In power supply devices, it is prevented to cool the components that actually do not need to be cooled.A power supply device includes a first converter configured to convert AC power from an AC power source into DC power, a second converter configured to convert a voltage to charge a backup electrical storage unit with the DC power from the first converter and to cause the electrical storage unit to discharge DC power, a plurality of cooling units configured to individually cool the first converter and the second converter, and a controller configured to change an operational state of the plurality of cooling units depending on an operational status of the power supply device.