A power supply system includes a first energy storage, a second energy storage, a power transmission circuit, and circuitry. The first energy storage outputs first output power to an electric load. The second energy storage outputs second output power to the electric load. The circuitry is configured to acquire a demand power to be supplied to the electric load. The circuitry is configured to acquire a remaining capacity value indicating remaining capacity in the second energy storage. The circuitry is configured to control the power transmission circuit to change a ratio of the first output power to the second output power to supply the demand power in accordance with the demand power and the remaining capacity value.