TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Metal: Metal (A) of the catalyst is one or more types chosen from lithium, group IIa element and group IIb element. Metal (B) of the catalyst is one or more types chosen from divalent metal which is preferably nickel. Metal (C) of the catalyst is aluminum.Preferred Composition: The catalyst is preferably porous spinel crystal-structured compound. The atomic ratio of metal (A) to metal (C) in the catalyst, is 0.01/2-1.5/2. The atomic ratio of metal (B) to metal (C) in the catalyst, is 0.01/2-1/2. EXAMPLE - Lithium nitrate (in g) (0.22) was dissolved in methanol (5 mL). Subsequently, porous gamma-alumina (1) having specific surface area of 150 m2/g was immersed in the solution, dried at 70 degrees C under reduced pressure, heated in air at 400 degrees C for 1 hour, and baked at 800 degrees C. A liquid consisting of nickel nitrate hexahydrate (0.41) dissolved in methanol (5 mL), was impregnated into the baked product. The baked product was dried at 70 degrees C under reduced pressure. The dried product was heated at 400 degrees C in air for 1 hour, baked at 900 degrees C, and a catalyst was produced. The catalyst had single-phase spinel crystal structure, and comprised spinel compound of formula: Li0.32Ni0.14Al2O3.6. Aluminum, lithium and nickel were uniformly dispersed in the catalyst, and the catalyst had 1.8 wt.% of lithium and 6.7 wt.% of nickel. The atomic ratio of lithium to aluminum, and nickel to aluminum, in the catalyst were 0.32/2 and 0.14/2, respectively. The catalyst was filled into a reactor. Nitrogen gas and oxygen gas were supplied into the reactor at 750 degrees C. Isooctane and water were introduced into the reactor, and oxidative steam reforming of isooctane was performed. The isooctane conversion ratio was 100%, after 5 hours from reaction initiation. The reaction gas contained 63 vol.% of hydrogen, 19 vol.% of carbon monoxide, 17 vol.% of carbon dioxide and 1 vol.% of methane. The hydrogen generation rate was 48.1 Nm3/kgh. The activity of the catalyst was not reduced during the reaction.