The power supply system includes: a fuel cell, capable of generating power; a power storage device, storing power generated by the fuel cell; and a control device, controlling at least the fuel cell. The control device, under a tendency that power consumption of a load at least connected with the fuel cell and the power storage device decreases, determines a first lower limit power based on power generated by the fuel cell before a predetermined time, causes the fuel cell to generate second power equal to or greater than the first lower limit power when first power generated by the fuel cell determined based on a power supplied to the load drops below the first lower limit power, and determines the first lower limit power with a tendency that the greater the generated power, the greater a difference between the generated power and the first lower limit power is increased.