TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The step of reacting aluminum and metal hydroxide to produce hydrogen is performed in a hydrogen supply system of a fuel cell vehicle. The step of obtaining the aluminum hydroxide comprises adding carbon dioxide to the sodium aluminum hydroxide to obtain an aluminum hydroxide. The method further comprises: obtaining a sodium carbonate in the step of adding carbon dioxide into the sodium aluminum hydroxide to obtain an aluminum hydroxide; obtaining a sodium hydroxide from the sodium carbonate; and re-supplying the sodium hydroxide as a raw material for producing the hydrogen. The heat-treating step is performed at 600-800 degrees C for 5-15 hours. The reducing step is performed through an electrolyte reduction of the aluminum oxide by adding calcium ions. The electrolyte reduction of the aluminum oxide with calcium ions utilizes an electrolyte including calcium oxide. The electrolyte reduction of aluminum oxide with calcium ions is performed at 400-600 degrees C. The electrolyte reduction of aluminum oxide with calcium ions is represented as given in the specification. The electrolyte reduction is performed by attaching the aluminum oxide on a surface of the aluminum. The reacting step further comprises: adding aluminum into a metal hydroxide aqueous solution, where the concentration of the metal hydroxide aqueous solution added with aluminum is 20-35%. The reacting step comprises reacting 3.3-7.5 pts. mol. of the metal hydroxide with 3 pts. mol. aluminum. The regenerating part performs a chemical reaction for regenerating the aluminum compound to the aluminum metal, the chemical reaction comprises: obtaining an aluminum hydroxide from the aluminum compound; heat-treating the aluminum hydroxide to obtain aluminum oxide; and reducing the aluminum oxide to obtain aluminum. Preferred Components: The metal hydroxide is a sodium hydroxide. The aluminum compound produced simultaneously with hydrogen is a sodium aluminum hydroxide. The calcium oxide in the electrolyte has a concentration of 0.1-1 mass%. The regenerating part is mounted outside of the fuel cell vehicle. The concentration of the aqueous solution of sodium hydroxide added to aluminum is 20-35%. The reducing of the aluminum by the electrolyte reduction comprises providing calcium ions from calcium oxide electrolyte. EXAMPLE - No suitable example given.