A power storage system of the invention, includes: a power generator; a first storage battery; a second storage battery having smaller capacitance than that of the first storage battery; a first switcher that connects or disconnects the first storage battery to or from a power supply line and a load device; a second switcher that connects or disconnects the second storage battery to or from the power supply line and the load device; a first switching unit that compares a voltage supplied to the load device with first and second predetermined threshold voltages and controls the first switcher according to a result of the comparison; and a second switching unit that compares the voltage supplied to the load device with third and fourth predetermined threshold voltages and controls the second switcher according to a result of the comparison.