A control device of a power supply system is configured to control inputting of electric power from a power system connected to a power distribution device to a plurality of strings connected to the power distribution device and outputting of electric power from the plurality of strings to the power system and to execute a process of stopping control for switching the at least one switching element between connection and disconnection on a string in which inputting of electric power and outputting of electric power are stopped out of the plurality of strings.