FUEL CELL SYSTEM

A fuel cell system includes a fuel cell that generates electricity by causing reaction of a fuel component contained in fuel gas, a supply path, a control valve, an ejector, a return path, and a controller. The control valve is provided on the supply path. The ejector is provided in a section on the supply path between the control valve and the fuel cell. The return path is connected between an exhaust port of the fuel cell and the ejector, and returns off-gas discharged from the exhaust port to the supply path by suction force generated by the ejector. The controller selectively executes a normal operation and a particular operation. In the particular operation, the control valve is continuously or intermittently opened to a second opening degree smaller than a first opening degree, when the fuel gas is supplied to the fuel cell at a first supply amount.