NOVELTY - A fuel cell system comprises raw fuel supply apparatus (1) which pumps raw fuel, hydrodesulfurization device (2) which removes sulfur raw fuel, hydrogen generator (3) containing modifier which modifies raw fuel from which sulfur is removed and produces fuel gas by hydrodesulfurization device, fuel cell (4) which produces electric power by making fuel gas and oxidizing agent gas react, 1st feed route (5) which connects raw fuel supply apparatus and hydrodesulfurization device, 2nd feed route (6) which connects hydrodesulfurization device and hydrogen generator, and fuel gas feed route (7).    USE - A fuel cell system for motor vehicles which use polymer electrolyte fuel cell or solid oxide fuel cell.    ADVANTAGE - Fuel cell system enables circulation of fuel gas by simple structure and prevents dew condensation water from being supplied to raw fuel supply apparatus.    DETAILED DESCRIPTION - A fuel cell system comprises raw fuel supply apparatus (1) which pumps raw fuel, hydrodesulfurization device (2) which removes sulfur raw fuel, hydrogen generator (3) containing modifier which modifies raw fuel from which sulfur is removed and produces fuel gas by hydrodesulfurization device, fuel cell (4) which produces electric power by making fuel gas and oxidizing agent gas react, 1st feed route (5) which connects raw fuel supply apparatus and hydrodesulfurization device, 2nd feed route (6) which connects hydrodesulfurization device and hydrogen generator, fuel gas feed route (7) which connects hydrogen generator and fuel cell, and recycle path (8) which branches from downstream path and supplies a part of fuel gas to 1st feed route from modifier. The fuel cell system draws in a part of fuel gas produced by hydrogen generator by raising flow rate of raw fuel containing sulfur pumped from raw fuel supply apparatus and is equipped with ejector (9) which supplies a part of raw fuel and fuel gas to hydrodesulfurization device and is provided in connection part of recycle path and 1st feed route. An INDEPENDENT CLAIM is included for hydrogen generating apparatus.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of a fuel cell system. (Drawing includes non-English language text).    Raw fuel supply apparatus (1)    Hydrodesulfurization device (2)    Hydrogen generator (3)    Fuel cell (4)    1st feed route (5)    2nd feed route (6)    Fuel gas feed route (7)    Recycle path (8)    Ejector (9)