2 battery type fuel cell system

2 battery type fuel cell system, the fuel is a reducing gas generated by a chemical reaction, and renewable fuels generating portion by the reverse reaction of the chemical reaction, the reducing gas supplied from the fuel generating section a generator-electrolysis unit having a power generation function and electrolysis of the electrolysis function oxidizing gas is a product of the reverse reaction is supplied from the fuel generating section during reproduction of the fuel generating section that generates electric power using, It comprises a circulation unit for forcibly circulating the gas containing the reducing gas and / or the oxidizing gas between the fuel generating section and the power generation and electrolysis unit, and a control unit for controlling said circulation portion . Then, the control unit controls the flow rate of the gas to be circulated by the circulation unit differently in the power generation operation and the charging operation.