A fuel cell system is provided which can extend the time during which a high-potential avoidance control is performed as much as possible, thereby reducing deterioration of a fuel cell. The fuel cell system includes: a fuel cell that generates electric power upon a supply of a reaction gas; a power storage device that is charged with at least a part of power generated by the fuel cell; and a controller that controls an output voltage of the fuel cell with, as an upper limit, a high-potential avoidance voltage lower than an open end voltage thereof. The controller variably sets the high-potential avoidance voltage in accordance with the amount of charge SOC of the power storage device.