A fuel cell system comprises a controller configured to: (i) calculate a torque target value of a compressor and an opening position target value of a pressure regulation valve from a flow rate target value of a cathode gas and a pressure target value of a cathode gas flow path, the flow rate target value of the cathode gas and the pressure target value being determined according to a required power output of a fuel cell stack; (ii) calculate a torque feedback value of the compressor from a difference between a flow rate measurement value and the flow rate target value of the cathode gas, and control the compressor using a torque command value obtained by adding the torque target value and the torque feedback value; and (iii) calculate an opening position feedback value of the pressure regulation valve from a difference between a pressure measurement value and the pressure target value of the cathode gas flow path, and control an opening position of the pressure regulation valve using an opening position command value obtained by adding the opening position target value of the pressure regulation valve and a delayed opening position feedback value that is obtained by delaying the opening position feedback value. This configuration suppresses the hunting of the flow rate and the pressure.