NOVELTY - Hydrogen-production apparatus has reaction unit (110) for producing sulfuric-acid and hydrohalide aqueous solutions (A,B), separation unit (120), hydrohalide concentration unit (130), halogenated hydrocracking unit (140) for decomposing hydrohalide into halogen and hydrogen, halogen-recycling unit (150) having vanadium-alloy film (151), sulfuric-acid concentration and decomposition units (160,170), and sulfur-dioxide recycling unit.    USE - For producing hydrogen.    ADVANTAGE - The hydrogen-production apparatus has excellent thermal efficiency, and efficiently produces hydrogen having excellent utility, without cooling hydrogen gas.    DETAILED DESCRIPTION - A hydrogen-production apparatus has a reaction unit (110) for reacting halogen such as iodine or bromine, sulfur dioxide and water, to produce sulfuric-acid aqueous solution (A) and hydrohalide aqueous solution (B), a separation unit (120) for separating solutions (A,B) by specific gravity difference, a hydrohalide concentration unit (130), a halogenated hydrocracking unit (140), a halogen-recycling unit (150), a sulfuric-acid concentration unit (160) for concentrating separated sulfuric-acid aqueous solution (A), a sulfuric-acid decomposition unit (170), and a sulfur-dioxide recycling unit. The unit (130) concentrates the separated hydrohalide aqueous solution, and unit (140) decomposes the concentrated hydrohalide into halogen and hydrogen. The unit (150) recycles halogen to the reaction unit, while separating hydrogen. The unit (170) decomposes the concentrated sulfuric acid into sulfur dioxide, oxygen and water. The sulfur-dioxide recycling unit recycles the sulfur dioxide to the reaction unit. The halogen recycling unit has a vanadium-alloy film (151) which separates hydrogen by pressure difference as a hydrogen separation membrane.    DESCRIPTION OF DRAWING(S) - The figure shows the outline block diagram of the hydrogen-production apparatus. (Drawing includes non-English language text).    reaction unit (110)    separation unit (120)    hydrohalide concentration unit (130)    halogenated hydrocracking unit (140)    halogen recycling unit (150)    vanadium alloy film (151)    sulfuric-acid concentration unit (160)    sulfuric-acid decomposition unit (170)