NOVELTY - A hydrogen gas production apparatus (1) comprises a microwave source that generates a microwave; a waveguide that applies microwave to dielectric hollow tube; and a gas supply source that supplies a hydrogen element-containing gas into dielectric hollow tube. The hydrogen element-containing gas supplied into the hollow tube undergoes plasma discharge with aid of microwave and produces reaction products including hydrogen gas through intramolecular bond breakage rather than heat decomposition, by collision of electron produced by microwave plasma discharge with hydrogen element-containing gas.    USE - The apparatus is used for producing hydrogen gas (claimed) for fuel cells.    ADVANTAGE - The apparatus has a simple constitution and provides small scaled production of the hydrogen gas in a simple, continuous and efficient manner. A solid carbon with high purity can be selectively recovered.    DETAILED DESCRIPTION - A hydrogen gas production apparatus comprises a dielectric hollow tube (10); a decompressing unit (50) for maintaining the dielectric hollow tube to a reduced pressure; a microwave source (30) that generates a microwave (40); a waveguide coupled to the microwave source that applies the microwave to the dielectric hollow tube; and a gas supply source (20) that supplies a hydrogen element-containing gas into the dielectric hollow tube. The hydrogen element-containing gas supplied into the dielectric hollow tube undergoes plasma discharge with aid of the microwave from the waveguide and produces reaction products including hydrogen gas through intramolecular bond breakage rather than heat decomposition, by collision of an electron produced by the microwave plasma discharge with the hydrogen element-containing gas. A pressure swing adsorption concentrator (60) is provided for separating the hydrogen gas from the reaction products. An INDEPENDENT CLAIM is also included for a method for producing hydrogen gas by a microwave plasma discharge.    DESCRIPTION OF DRAWING(S) - The figure is a cross-sectional view showing a hydrogen gas production apparatus.    Hydrogen gas production apparatus (1)    Dielectric hollow tube (10)    Gas supply source (20)    Microwave source (30)    Microwave (40)    Decompressing unit (50)    Pressure swing adsorption concentrator (60)