TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred System: Alternatively, the hydrogen separation mold hydrogen production system which has the hydrogen separation mold steam reforming device by the steam reforming of hydrocarbon fuel, a combustor which is the heat sources for steam reforming of the hydrocarbon fuel, and a boiler for water vapor production of the hydrocarbon fuel for reformation, comprises: (a) carbon monoxide selection methanation device which selectively carries out methanation of carbon monoxide in hydrogen separated from reformed gas in the hydrogen separation mold steam reforming device; (b) carbon monoxide selective-oxidation device which selectively oxidizes carbon monoxide in off gas which is remaining gas after separating hydrogen from reformed gas in the hydrogen separation mold steam reforming device; (c) water separator which separates water from the off gas after cooling off gas from the carbon monoxide selective-oxidation device; (d) flow director of off gas separated with the water separator, and carbon-dioxide liquefaction recovery apparatus containing water content adsorption tower, methane separation apparatus, compressor, heat of cooling exchanger, and gas-liquid separation tank is comprised one by one; (e) a methane separation apparatus, where after separating methane in the off gas which passed through the water-content adsorption tower and raising carbon dioxide levels, one by one, it transduces into a compressor, a heat-of-cooling exchanger, and a gas-liquid separation tank, and liquid dioxycarbons are recovered; and (f) recycler of off gas (methane rich gas) from the methane separation apparatus, and carbon-dioxide separation completed off gas from the gas-liquid separation tank as a fuel of combustor of hydrogen separation mold modifier. In a second alternative case, the hydrogen separation mold hydrogen production system which has the hydrogen separation mold steam reforming device by the steam reforming of hydrocarbon fuel, a combustor which is the heat sources for steam reforming of the hydrocarbon fuel, and a boiler for water vapor production of the hydrocarbon fuel for reformation, comprises: (a) carbon monoxide selection methanation device which selectively carries out methanation of carbon monoxide in hydrogen separated from reformed gas in the hydrogen separation mold steam reforming device; (b) carbon monoxide selective-oxidation device which selectively oxidizes carbon monoxide in off gas which is remaining gas after separating hydrogen from reformed gas in the hydrogen separation mold steam reforming device; (c) water separator which separates water from the off gas after cooling off gas from the carbon monoxide selective-oxidation device; (d) flow director of off gas separated with the water separator, and carbon-dioxide liquefaction recovery apparatus containing water content adsorption tower, carbon-dioxide levels enrichment apparatus, compressor, heat-of-cooling exchanger, and gas-liquid separation tank is comprised one by one; (e) carbon-dioxide-levels enrichment apparatus, where after raising the carbon dioxide levels in the off gas which passed through the water-content adsorption tower, one by one, it introduces into a compressor, a heat-of-cooling exchanger, and a gas-liquid separation tank, and comes to recover a liquid dioxycarbon; and (f) it goes to recycle of off gas from the carbon-dioxide-levels enrichment apparatus, and carbon-dioxide separation completed off gas from the gas-liquid separation tank as a fuel of combustor of hydrogen separation mold modifier. The carbon monoxide selection methanation device is installed in the upper part of the hydrogen separation mold steam reforming device; furthermore, the carbon monoxide selective-oxidation device is installed in the upper part. The hydrogen separation mold reformation system installed by the hydrogen station of an on-site system. The hydrocarbon fuel is a natural gas or town gas. The heat of combustion exhaust gas in the combustor is utilized for the heating of the hydrocarbon fuel or for heating of the fuel gas for boilers or for heating of the water supplied into a boiler.