NOVELTY - The carbon monoxide (CO) removal apparatus comprises a CO removal device (1) containing a catalyst layer (2) having a catalyst which performs an oxidation reaction with CO and oxygen in air, a reformed-gas supply path (8), an air supply path (9), an air feeder (5) and a unit to supply air containing oxygen when the temperature measured in the apparatus is less than a predetermined temperature.    USE - For removing CO from reformed gas using hydrocarbon group fuels, such as alcohol, methanol, butane, propane gas, methane gas and liquefied petroleum gas.    ADVANTAGE - The CO removal apparatus raises the temperature of the catalyst layer using the heat produced by the catalyst during combustion reaction in the catalyst layer. The catalyst layer provides a predetermined temperature region to the CO removal apparatus within reduced time.    DETAILED DESCRIPTION - The carbon-monoxide (CO) removal apparatus reduces CO from the reformed gas which is rich in hydrogen produced by performing water vapor modification reaction of a fuel and water component. The CO removal apparatus comprises a CO removal device (1) containing a catalyst layer (2) which contains a catalyst, a reformed-gas supply path (8), an air supply path (9) and an air feeder (5). The catalyst performs an oxidation reaction with CO and oxygen in air. The reformed-gas supply path supplies reformed gas to the CO removal device and the air supply path supplies air to the reformed gas. The air feeder adjusts the amount of air supply to the air supply path and the CO removal device measures the temperature of the catalyst layer. The CO removal apparatus contains a unit to supply air containing oxygen more than 5.5 times of the reaction equivalent with the CO contained in the reformed gas in an air feeder when the temperature is less than a predetermined temperature.    An INDEPENDENT CLAIM is included for the CO removal method which reduces CO from the reformed gas and measure the temperature of the catalyst layer and judges whether the temperature is lower than the predetermined temperature.    DESCRIPTION OF DRAWING(S) - The figure shows the schematic diagram of catalyst removal apparatus. (Drawing includes non-English language text).    Carbon-monoxide removal device (1)    Catalyst layer (2)    Air feeder (5)    Reformed-gas supply path (8)    Air supply path (9)