NOVELTY - A copper-zinc-aluminum catalyst comprises (in %mass by oxide conversion) copper (60-90), zinc (2-15), aluminum (5-30), and oxygen. The catalyst has specific surface area of 50-200 m2/g, crystalline diameter of 200 Angstrom or less, volume density of 0.6-2 g/cm3, pore volume of 0.3-0.6 cm3/g, and average pore radius of 45-120 Angstrom . The X-ray diffraction pattern of the catalyst has a broad peak of 1 half value width or more in lattice space (d: Angstrom ) of 2.44 plus minus 0.05 and 2.86 plus minus 0.05. A peak does not exist in lattice space of 2.48 plus minus 0.05, 2.81 plus minus 0.05 and 2.6 plus minus 0.05.    USE - Copper-zinc-aluminum catalyst is used in carbon monoxide conversion in hydrogen production (all claimed) for fuel cells used in domestic applications and vehicles. Can also be used as hydrogen production catalyst, methanol synthesis catalyst, high-temperature shift catalyst of water gas shift reaction, and steam reforming catalyst of methanol.    ADVANTAGE - The copper-zinc-aluminum catalyst exhibits excellent activity and durability even during repeated increase/decrease of temperature. Since pore diameter is large, diffusibility of reaction material inside the catalyst is excellent.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) manufacture of copper-zinc-aluminum catalyst, which involves using a catalyst precursor obtained by mixing and coprecipitating sodium hydroxide and nitrate-containing solution containing copper, zinc and aluminum. The solutions are mixed such that the molar ratio of sodium hydroxide and nitrate is 0.94-1;    (2) carbon-monoxide conversion, which involves reducing the carbon monoxide conversion in a hydrogen-containing gas containing carbon monoxide by water gas shift reaction at 150-500 degrees C; and    (3) hydrogen production, which involves reducing carbon monoxide concentration of hydrogen-containing gas obtained by carbon-monoxide conversion by reaction other than carbon monoxide selective oxidation.