NOVELTY - A fuel cell system has a fuel cell (10), a fuel gas supply path (11), a fuel gas circuit, an oxidizing agent gas supply path (12), a fuel waste gas path, a purge unit, a scavenging-air unit, a shut-off valve, a flow regulating valve and a control unit. The fuel cell produces electric power by carrying out reaction between fuel gas supplied to an anode (10a), and oxidizing agent gas supplied to a cathode (10b). The fuel gas supply path supplies fuel gas to the anode. The oxidizing agent gas supply path supplies oxidizing agent gas to the cathode.    USE - Fuel cell system is used for vehicle, vessel and aircraft.    ADVANTAGE - The fuel cell system has reduced size and weight.    DETAILED DESCRIPTION - A fuel cell system has a fuel cell (10), a fuel gas supply path (11), a fuel gas circuit, an oxidizing agent gas supply path (12), a fuel waste gas path, a purge unit, a scavenging-air unit, a shut-off valve, a flow regulating valve and a control unit. The fuel cell produces electric power by carrying out reaction between fuel gas supplied to an anode (10a), and oxidizing agent gas supplied to a cathode (10b). The fuel gas supply path supplies fuel gas to the anode. The oxidizing agent gas supply path supplies oxidizing agent gas to the cathode. The fuel gas circuit returns fuel gas which passed the anode to the fuel gas supply path. The fuel waste gas path discharges fuel waste gas from the anode. The purge unit purges fuel waste gas from the fuel waste gas path. Scavenging gas is introduced into the anode. The scavenging-air unit scavenges residual gas in the anode and the fuel gas circuit through the fuel waste gas path. The shut-off valve and the flow regulating valve are arranged in series on the fuel waste gas path and carry out opening-and-closing control. The control unit controls scavenging-air flow rate during scavenging air by the scavenging-air unit and the purge flow rate during purging by the purge unit by controlling the shut-off valve and the flow regulating valve.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of the fuel cell system. (Drawing includes non-English language text)    Fuel cell (10)    Anode (10a)    Cathode (10b)    Fuel gas supply path (11)    Oxidizing agent gas supply path (12)