NOVELTY - Manufacturing apparatus of hydrogen-containing gas has modification mechanism in which modification processing of hydrocarbon fuel is performed, carbon monoxide removal mechanism in which carbon monoxide is removed by converting carbon dioxide in the obtained gas into carbon monoxide, and hydrocarbon compound removal mechanism in which 2C or more hydrocarbon compound in hydrogen-containing gas is absorbed and removed.    USE - For manufacturing hydrogen-containing gas used for fuel cell system (both claimed) such as solid polymer-type fuel cell, phosphoric acid-type fuel cell, molten carbonate-type fuel cell and solid oxide-type fuel cell used for motor vehicles, for converting chemical energy into electrical energy.    ADVANTAGE - The apparatus efficiently produces hydrogen-containing gas containing reduced amount of hydrocarbon compound, by efficiently removing hydrocarbon compound in the gas. The fuel cell system using the hydrogen-containing gas, has excellent durability.    DETAILED DESCRIPTION - The manufacturing apparatus of hydrogen-containing gas has modification mechanism in which modification processing of hydrocarbon fuel is performed, carbon monoxide removal mechanism in which carbon monoxide is removed by converting carbon dioxide in gas generated from modification mechanism into carbon monoxide, and hydrocarbon compound removal mechanism in which 2C or more hydrocarbon compound in hydrogen-containing gas obtained from carbon monoxide removal mechanism is absorbed and removal. The hydrocarbon compound removal mechanism reduces 2C or more hydrocarbon compound in hydrogen-containing gas into 1 volume ppm using adsorption agent such as activated carbon, silica and/or zeolite.    INDEPENDENT CLAIMS are also included for:    (1) manufacture of hydrogen-containing gas; and    (2) fuel cell system.    DESCRIPTION OF DRAWING(S) - The figure shows the hydrocarbon compound removal mechanism after selective-oxidation reaction of carbon monoxide during manufacture of the hydrogen-containing gas. (Drawing includes non-English language text).