A power supply system includes: an inter-load switch including a first switch and a second switch connected in series, a voltage generation unit, an electric storage device connected between the first switch and the second switch, a first state control unit configured to select a first state in which power is supplied from at least one of the voltage generation unit or the electric storage device to a first load and a second load, and a second state control unit configured to, when determining that a failure has occurred, select a second state in which power is supplied from the electric storage device to a load on a side of a no-failure-occurrence system in which no failure has occurred, by turning off a switch on a side of a failure-occurrence system in which a failure has occurred and turning on a switch on a side of the no-failure-occurrence system.