NOVELTY - A hydrocarbon gas after desulfurization is reformed by contacting with reforming catalyst to obtain high concentrated hydrogen-containing gas. The carbon monoxide or water vapor present in gas is converted into carbon dioxide and hydrogen respectively. Reformed gas ingredients other than hydrogen are absorbed and high purity hydrogen gas is then purified and supplied through hydrogen separation membrane.    USE - For manufacture of ultrapure hydrogen from hydrocarbon, such as natural gas, liquefied petroleum gas, naphtha and methanol.    ADVANTAGE - Ultrapure hydrogen of 99.99999 wt.% (7N) is obtained. A heat exchange unit used for heating high concentrated hydrogen containing gas enables reduction of installation and running cost. The unwanted breed gas from the hydrogen separation membrane is effectively used as hydrogen gas for hydrodesulfurization, as heating gas and for purification of hydrogen. Hence high purity hydrogen is obtained at low cost. The heat generated in the water vapor reformer is utilized for operation of hydrogen separation in hydrogen separation membrane.    DETAILED DESCRIPTION - A raw hydrocarbon gas is desulfurized and steam reformed by heating mixed fluid at predetermined temperature and contacting with reforming catalyst after adding water or water vapor to the desulfurized hydrocarbon to form high concentrated hydrogen containing gas. The high concentrated hydrogen containing gas is cooled to predetermined temperature and contacted with a conversion catalyst. The concentration of hydrogen is increased by removing carbon monoxide or water vapor present in gas by converting into carbon dioxide and hydrogen respectively. The reformed gas ingredients other than hydrogen are absorbed by an absorbent by pressure swing absorption method (PSA) to obtain high purity hydrogen gas. The high purity hydrogen gas is then heated to predetermined temperature, purified and supplied through hydrogen separation membrane to obtain ultrapure hydrogen.    An INDEPENDENT CLAIM is also included for apparatus for manufacture of ultrapure hydrogen comprising a desulfurization unit (12) for desulfurization of hydrocarbon, steam reforming unit (13) for producing hydrogen containing gas and gas conversion unit (18) for converting carbon monoxide and water vapor into carbon dioxide and hydrogen respectively. An absorbent removes reformed gas component other than hydrogen and PSA unit (19) carries purification of high purity hydrogen gas. A membrane separation unit (21) installed with hydrogen separation membrane (20) separates ultrapure hydrogen.    DESCRIPTION OF DRAWING(S) - The figure shows systematic diagram of desulfurization reformer of hydrocarbon. (Drawing includes non-English language text).    Desulfurization unit (12)    Steam reforming unit (13)    Water vapor reformer (15)    Raw material preheating unit (16)    Raw material heater (17)    Gas conversion unit (18)    PSA unit (19)    Hydrogen separation membrane (20)    Membrane separation unit (21)