Fuel cell system

A fuel cell system includes a fuel cell and a secondary battery used as power sources of a power supply target object, and a control device for controlling driving of the power supply target object. The control device determines whether a predetermined condition required for activation of the fuel cell is satisfied, permits a battery-driven mode in which the power supply target object is driven using only the secondary battery when the predetermined condition is satisfied, and prohibits the battery-driven mode when the predetermined condition is not satisfied.