NOVELTY - Manufacture of hydrogen gas from a gas, where combustible material is methane fermented and treated with reforming process and modifying process, involves carrying out a carbon dioxide amine absorption process and then a methanation process.    USE - The hydrogen is used in the production of electric power using a fuel cell.    ADVANTAGE - Chemical energy from combustible material is highly efficiently converted to electrically energy.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a fuel cell electricity generating method comprising methane fermentation of organic material, manufacturing hydrogen-containing gas by reforming the digestion gas obtained by methane fermentation and a fuel cell electricity generating process, where the gas treating process comprises adsorption and/or absorption removal of acidic gas of hydrogen sulfide and hydrogen chloride etc, reforming methane to hydrogen and carbon monoxide by a catalytic reaction with water vapor, modifying the carbon monoxide to hydrogen and carbon dioxide by catalytic reaction with water vapor, absorption separation by contacting carbon dioxide with water or alkaline solution and/or amine absorption separation process by contact with an amine absorption liquid, and a methanation reaction by removing carbon monoxide and carbon dioxide by methanation reaction with hydrogen, and the fuel cell electricity generating process involves using the oxygen-containing gas obtained from the methanation process as a fuel gas and supplying to the anode and cathode of a fuel cell stack;    (2) a hydrogen refining method; and    (3) a fuel cell electricity generating system.    DESCRIPTION OF DRAWING(S) - The figure is a drawing showing the fuel cell electricity generating system (drawing includes non-English language text).    Methanation Fermentation Process (A)    Power Generating Process (C)    Organic Substance (a)    Digestion Gas (b)    Hydrogen-Containing Gas (c)    Pretreatment Step (1)    Reforming Step (2)    Modifying Step (3)    Carbon Dioxide and Water Absorbing Step (4)    Carbon Dioxide and Amine Absorbing Step (5)    Methanation Step (6)    Boiler (11)    Steam (12)    Water for Absorbing Carbonic Acid (01)    Water having Absorbed Carbon Dioxide (02)    Carbon Dioxide (03)    Anode Offgas (04)    Oxygen-Containing Gas (05)    Cathode Offgas (06)    Exhaust Heat (07)    Exhaust Gas (08)