NOVELTY - A hydrogen-rich fuel gas is produced by supplying a reformed gas to a pressure swing adsorption mechanism for removing impurities from the reformed gas to refine the reformed gas into a hydrogen-rich fuel gas.    USE - For producing a hydrogen-rich fuel gas.    ADVANTAGE - The method does not use any off gas holder in which the exhaust gas is clean. It produces a hydrogen-rich fuel gas efficiently.    DETAILED DESCRIPTION - Production of a hydrogen-rich fuel gas involves reforming a fuel to obtain a reformed gas; and supplying the reformed gas to a pressure swing adsorption mechanism for removing impurities from the reformed gas to refine the reformed gas into the hydrogen-rich fuel gas. The impurities are continuously supplied to a heating unit as a heat source fuel, and combustion air is supplied to the heating unit for inducing combustion. The amount of the combustion air supplied to the heating unit is controlled synchronously with the change in the amount of heat energy of the impurities supplied to the heating unit.    An INDEPENDENT CLAIM is also included for a fuel gas production apparatus (10) for reforming a fuel to produce a hydrogen-rich fuel gas comprising vaporization mechanism having a combustion catalyst for vaporizing the fuel; reforming mechanism for reforming the vaporized fuel to obtain a reformed gas; pressure swing adsorption mechanism for removing impurities from the reformed gas to refine the reformed gas into the hydrogen-rich fuel gas; supply passage for continuously supplying the impurities discharged from the pressure swing adsorption mechanism to the combustion catalyst or another unit which requires a heat source fuel; combustion air supply mechanism for supplying combustion air to the combustion catalyst; and control unit for controlling the amount of the combustion air supplied to the combustion catalyst synchronously with the change in the amount of heat energy of the impurities supplied to the combustion catalyst.    DESCRIPTION OF DRAWING(S) - The figure is a fuel gas supply system.    Apparatus (10)    Fuel gas supply system (12)