A fuel cell system is provided with a fuel cell for supplying generated electric power to external power loads connected to a system power source, a reforming apparatus for supplying fuel gas generated by reforming unreformed fuel to the fuel cell, and a controller for controlling the operations of the fuel cell and the reforming apparatus. When having been unable to normally stop the fuel cell system due to the system power source falling in a power failure, the controller automatically executes a recovery operation so that the fuel cell system is brought into a restartable state, and upon completion of the recovery operation, brings the fuel cell system into a standby state. Thus, a normal restart subsequent to a power failure becomes possible without the need for human labor.