TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Properties: The particle size of the oxide particles is 1/400-1/10 times the average pore size of the porous inorganic base material. The average particle diameter of the oxide particles is 10-200 nm.Preferred Component: The porous inorganic base material is corderite. The oxide particles comprise at least one compound chosen from cerium oxide, zirconia, alumina, titania, silica, magnesia, yttria and their derivatives, and are theta-alumina, delta-alumina or alpha-alumina. The catalyst particles contain base particles which are one or more of single substance microparticles having a primary particle diameter of nanometer order, as a catalyst component. Metal(s) or their alloys are coated on at least one portion of the surface of base particles. The base particles comprise metal oxide, metal carbide and/or carbon material. The metal oxide comprises an oxide or two or more types of solid solution of cerium, zirconium, aluminum, titanium, silicon, magnesium, tungsten and strontium. The metal carbide comprises silicon carbide or its derivative(s). The carbon material is graphite. The metals or their alloys coated on the base particles are ultrafine particles with particles size of less than 50 microns, or a coating layer containing 1-30 atomic layers. The metals or their alloys coated on the base particles have a purity of 99% or more. The metals or their alloys are coated on the partial surface of the base particles. The metals or their derivatives in the catalyst component are simple substance chosen from platinum, rhodium, palladium, gold, silver, ruthenium or their oxides, or two or more types of solid solution.Preferred Process: An organic material solution is applied on the surface of the inorganic base material, to form a film (F) having a thickness of 10-20000 nm. Oxide particles with a catalyst component are arranged on the film. A coat layer is formed on the surface of base material by baking the film after an appropriate time. Alternately, a mixed solution of organic material and oxide particles with a catalyst component, or a mixed solution of organic material, oxide particles and catalyst component, is applied on the surface of the base material. The viscosity of the mixed solution is 3-100 mPa.second. A film (F) is formed on the base material, and oxide particles and catalyst component are arranged on the film. The catalyst component is supported on the oxide particles by baking the film (F).    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The organic material is polyvinyl alcohol, polyethylene glycol, polyvinyl pyrrolidone, trehalose and/or their mixtures.