NOVELTY - A carbon monoxide selective-oxidation catalyst component (1) comprises a catalyst substance (2) having priority over oxidation reaction of hydrogen in presence of water vapor, and a water supplying component (3). The catalyst substance catalyzes the oxidation reaction of carbon monoxide in hydrogen rich gas containing carbon monoxide. The water supplying component is provided in position contacting with catalyst substance, and provides water vapor to the vicinity of catalyst substance.    USE - Carbon monoxide selective-oxidation catalyst component is used for carbon monoxide selective-oxidation filter for carbon monoxide selective removal apparatus (both claimed). Can also be used for hydrogen-oxygen fuel cell used for heat engines and thermal power generation.    ADVANTAGE - The carbon monoxide selective-oxidation catalyst component provides favorable fuel utilization efficiency and electric power generation efficiency. The carbon monoxide selective removal apparatus has excellent carbon monoxide removal capability. The consumption of hydrogen is reduced by selectively oxidizing carbon monoxide in the reformed gas.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) carbon monoxide selective-oxidation filter, which has substrate and carbon monoxide selective-oxidation catalyst component coated on the surface of substrate through direct or base layer; and    (2) carbon monoxide selective removal apparatus, which comprises hydrogen gas supply portion, oxygen gas supply section, catalytic reaction portion provided with carbon monoxide oxidation filter, and temperature control portion. The hydrogen gas supply portion includes hydrogen rich gas containing carbon monoxide. The oxygen gas supply section supplies oxygen for mixing with hydrogen gas. The temperature control portion controls the temperature of carbon monoxide selective-oxidation filter in the catalytic reaction portion.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of catalyst component.    Catalyst component (1)    Catalyst substance (2)    Water supplying component (3)