A fuel cell system according to one embodiment performs refresh control of an electrode catalyst of a fuel cell, by reducing a stack voltage as a voltage of the fuel cell to a refresh voltage at which the electrode catalyst is activated. The system includes the fuel cell that generates electric power by an electrochemical reaction using fuel gas and oxidation gas, a stack voltage sensor that sensors the stack voltage, and a controller that controls power of the fuel cell. When a high load demand that makes the stack voltage lower than a given voltage is made on the fuel cell, the controller causes the fuel cell to deliver power commensurate with the high load demand, and performs refresh control when the stack voltage becomes lower than the given voltage through the above control.