A fuel cell system according to the present invention includes a fuel cell; a fuel supply system for supplying a fuel gas to the fuel cell; an injector which drives a valve body with an electromagnetic driving force in a predetermined driving period to detach the valve body from a valve seat, whereby a gas state on the upstream side of the fuel supply system is adjusted to jet the gas to a downstream side; and a control device which controls the operation of the injector. The control device allows the injector to jet the gas with a jet flow rate of a predetermined jet flow rate or less in a case where the demanded amount of a power to be generated with respect to the fuel cell is the predetermined amount of the power to be generated or less, and the control device sets the driving frequency of the injector in accordance with the jet flow rate and the demanded amount of the power to be generated.