A power supply system includes a power conversion circuit that is connectable to a power storage unit. The power supply system includes a control unit and a heat transferring unit. The control unit supplies a current between the power storage unit and the power conversion circuit by performing on-off control of a switch that configures the power conversion circuit. The heat transferring unit absorbs heat that is generated in the power conversion circuit in accompaniment with the on-off control of the switch and transfers the heat to a temperature-increase target element. The control unit performs temperature-increase mode control in which the switch is on-off controlled such that an amount of heat that is generated in the power conversion circuit is increased when a temperature-increase request for the temperature-increase target element is present, compared to when the temperature-increase request is not present.