NOVELTY - The fuel reformer for generating hydrogen gas, comprises a combustion space, a catalytic reforming passage, a hydrogen permeable membrane, a hydrogen collecting space, a reformate gas supply passage, a fuel vapor passage and a stack of fuel reforming units. The fuel reformer reforms a hydrocarbon material into hydrogen gas. The combustion space generates a combustion heat by burning a fuel in an oxidant gas supplied from outside of the unit. The catalytic reforming passage comprises a reforming catalyst that reforms the hydrocarbon material into a reformate gas containing hydrogen.    USE - Useful for generating hydrogen gas for a fuel cell power plant. Useful for supplying the generated hydrogen gas to a heating structure of reforming element.    ADVANTAGE - The fuel reformer increases heat transfer efficiency from the combustion element to the fuel reforming element.    DETAILED DESCRIPTION - The fuel reformer for generating hydrogen gas, comprises a combustion space, a catalytic reforming passage, a hydrogen permeable membrane, a hydrogen collecting space, a reformate gas supply passage, a fuel vapor passage and a stack of fuel reforming units. The fuel reformer reforms a hydrocarbon material into hydrogen gas. The combustion space generates a combustion heat by burning a fuel in an oxidant gas supplied from outside of the unit. The catalytic reforming passage comprises a reforming catalyst that reforms the hydrocarbon material into a reformate gas containing hydrogen. The catalyst is heated by the combustion heat and generated by the combustion space. The catalytic reforming passage is disposed in parallel with the combustion space. The hydrogen permeable membrane faces the catalytic reforming passage and extracts hydrogen in the reformate gas. The hydrogen collecting space collects the hydrogen extracted by the hydrogen permeable membrane. The reformate gas supply passage supplies the reformate gas from the hydrogen in which the hydrogen extracts the combustion space. The fuel vapor passage generates a fuel vapor in which a mixture of the hydrocarbon material and water in a vaporized form, and supplies the fuel vapor to the catalytic reforming passage. The oxidant gas in the combustion space and the fuel vapor in the catalytic reforming passage have opposite flow directions to one another. Passage supplies the fuel to the combustion space from the outside of the unit. The combustion space has an inlet that introduces the oxidant gas, and an outlet that discharges the combustion gas. The reformate gas supply passage has openings, which is used to supply the reformate gas to the oxidant gas flow region in the combustion space. The openings have horizontal opening that faces the oxidant gas flow in a lateral direction from the outside and the inside of the flow. The openings have vertical opening that faces the flow of oxidant gas in a lateral direction from an opposite side of the combustion space to the catalytic reforming passage. An upstream part of the combustion space has a larger cross-sectional area than a downstream part. The opening faces the upstream portion of the oxidant gas flow disposed at smaller intervals than a downstream portion of the oxidant gas flow. Wall surfaces are used to form the combustion space that supports an oxidation catalyst. Porous body is enclosed in the combustion space. The porous body has a central region porous body, which supports an oxidation catalyst and disposes in a central region of the combustion space. A pair of boundary region porous bodies is disposed on both sides of the centered region porous body in the combustion space. The oxidant gas flow is formed through the central region porous body, and the pair of the boundary region porous bodies has a greater gas flow resistance than the central region porous body. The reformate gas supply passage has a pair of reformate gas supply spaces, which faces the pair of boundary region porous bodies from the opposite direction to the central region porous body to supply the reformate gas to the first porous body through the pair of boundary region porous bodies. The reformate gas supply passage has a pair of connection passages disposed in parallel with the pair of the reformate gas supply spaces and connected to an outlet of the catalytic reforming passage. The passages connections are communicates with the reformate gas supply space through-holes. The gas flow resistance in the upstream part of the boundary region porous bodies is set to be greater than a gas flow resistance in a downstream part of the boundary region porous bodies to the oxidant gas flow in the central region porous body. The operation pressure in the combustion space is lower than operation pressure in the catalytic reforming passage. The stack of fuel reforming units comprises the combustion space, the catalytic reforming passage, the hydrogen permeable membrane and the hydrogen gas collecting space, which are formed in a plate-shaped element.    DESCRIPTION OF DRAWING(S) - The diagram shows a fuel reformer:    Hydrogen gas collecting element; (10)    Plate-shaped permeable element; (20)    Plate-shaped reforming element; (30)    Plate-shaped combustion element; (40)    Partition plates. (50)