A control device switches between a first injection control of injecting the fuel gas by sequentially providing periods during which at least one of the plurality of injectors injects the fuel gas if it is determined that the power generation state of the fuel cell stack is stable based on a detected power generation state, and a second injection control of injecting the fuel gas by intermittently providing periods during which the plurality of injectors simultaneously inject the fuel gas if it is determined that the power generation state of the fuel cell stack is not stable based on the detected power generation state.