FUEL CELL DEVICE

To provide a fuel cell device capable of increasing a fuel utilization rate while the operation state of a fuel cell is stable.SOLUTION: In a fuel cell device, when an operation controller 16 executes fuel utilization rate increasing processing for increasing a fuel utilization rate in a fuel battery 10 by reducing the supply amount of a raw fuel gas to a reforming unit 7 to a target fuel supply amount and reducing the supply amount of a reforming water to the reforming unit 7 to a target water supply amount in a state where the output current of the fuel battery 10 is stable, the operation controller 16 determines whether a predetermined processing continuing condition is satisfied after controlling the operation of a water supply amount adjusting unit 4 to start reduction of the supply amount of the reforming water to the reforming unit 7, and starts to reduce the supply amount of the raw fuel gas to the reforming unit 7 after the processing continuing condition is satisfied.SELECTED DRAWING: Figure 1 【課題】燃料電池の運転状態が安定したままで燃料利用率を上げることができる燃料電池装置を提供する。【解決手段】燃料電池装置において、運転制御部１６は、燃料電池１０の出力電流が安定した状態で、改質部７への原燃料ガスの供給量を目標原燃料供給量まで減少させ且つ改質部７への改質用水の供給量を目標水供給量まで減少させることで燃料電池１０での燃料利用率を上昇させる燃料利用率上昇処理を行う場合、水供給量調節部４の動作を制御して改質部７への改質用水の供給量の減少を開始した後に所定の処理継続条件が満たされたか否かを判定し、処理継続条件が満たされた後に改質部７への原燃料ガスの供給量の減少を開始させる。【選択図】図１