FUEL CELL SYSTEM

PROBLEM TO BE SOLVED: To provide a fuel cell system by which driving performance of a vehicle mounted with a fuel cell is improved.SOLUTION: The fuel cell system includes a gradient sensor 60 or a navigation system 74 and a fuel cell ECU 24. The fuel cell ECU 24 includes: a determination means which determines as an intermittent operation power generation shutdown condition completion to perform power generation operation shutdown or the like of the fuel cell stack 12 when a certain condition is satisfied; an execution means; and a prohibition means. The execution means executes the intermittent operation power generation shutdown when the vehicle is not at a stop or not running at an uphill and is determined to satisfy the intermittent operation power generation shutdown condition completion. The prohibition means prohibits the intermittent operation power generation shutdown when either one or both of the cases are satisfied that the vehicle is at a stop or running at an uphill and that the determination means determines that the intermittent operation power generation shutdown condition completion is not completed.