NOVELTY - The polymer electrolyte fuel cell electric power generation system has a hydrogen-production apparatus (1) with modification reaction device (3), carbon monoxide shift device (4), carbon monoxide selective-oxidation device (6) and auxiliary combustor (19), polymer electrolyte fuel cell (2), and cathode waste-gas injection piping (P) or combustion exhaust gas injection piping (27a). Piping (P) supplies cathode waste gas ejected from the fuel cell to device (4), and piping (27a) throws some combustion exhaust gas of combustor into device (4).    USE - For generating electric power.    ADVANTAGE - The polymer electrolyte fuel cell electric-power generation system uniformly mixes reformed gas and carbon monoxide selective-oxidation agent, without causing increase in power consumption.    DETAILED DESCRIPTION - The polymer electrolyte fuel cell electric power generation system has a hydrogen-production apparatus (1) comprising a modification reaction device (3), a carbon monoxide shift device (4), carbon monoxide selective-oxidation device (6) and auxiliary combustor (19), polymer electrolyte fuel cell (2), and cathode waste-gas injection piping or combustion exhaust gas injection piping (27a). The device (3) produces reformed gas containing hydrogen by using a hydrocarbon, alcohol or an ether fuel, oxygen or air, water, or water vapor as a raw material. The carbon monoxide contained in reformed gas is reacted with water vapor in the device (4). The device (6) decreases carbon monoxide concentration of reformed gas, which passed through the device (4). The combustor carries out combustion processing and heat recovery of anode waste gas of fuel cell. The fuel cell generates electric power considering the reformed gas, which passed through the device (4) as a fuel. The cathode waste-gas injection piping supplies cathode waste gas ejected from the fuel cell to device (4), and combustion exhaust gas injection piping throws some combustion exhaust gas of combustor into device (4).    DESCRIPTION OF DRAWING(S) - The figure shows the schematic diagram of polymer electrolyte fuel cell electric-power generation system. (Drawing includes non-English language text)    Hydrogen production apparatus (1)    Polymer electrolyte fuel cell (2)    Modification reaction device (3)    Carbon monoxide shift device (4)    Carbon monoxide selective-oxidation device (6)    Auxiliary combustor (19)    Combustion exhaust gas injection piping (27a)