The present invention provides a method of producing a CuZnAlZr oxide catalyst consisting of reacting an aqueous NaOH solution and aqueous Na₂CO₃ solution with a mixture of aqueous solutions of each nitrate of Cu, Zn, Al, and Zr, producing a precipitate by coprecipitation, aging, filtering, washing and drying this precipitate to prepare a catalyst precursor consisting of a CuZnAlZr layered double hydroxide, and then obtaining a CuZnAlZr oxide by calcining this precursor in an air ambient atmosphere, a CuZnAlZr oxide catalyst, a CuZnZrCe oxide catalyst, a CoCuZnAl oxide catalyst for producing hydrogen by oxidative steam reforming a methanol, and methods of producing hydrogen gas consisting of converting methanol to hydrogen gas by oxidative steam reforming in the presence of air and steam using these oxide catalysts.