TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The complex oxide contains at least 1 ion containing gold, platinum, or palladium in ion exchange site, in addition to aluminum ion. The oxidation state of supported gold, platinum, or palladium is zero when the ion containing gold, platinum, or palladium is decomposed and reduced. The oxidation number of supported silver, copper, manganese, cobalt, or iron is 1 or more, when the ion containing silver, copper, manganese, cobalt, or iron is decomposed. The complex oxide contains ion which contains titanium in ion exchange site, in addition to aluminum ion. The oxidation number of the supported titanium is 4 when the ion containing titanium is decomposed. The ratio of silica and alumina is 100 or less. The complex oxide is zeolite.Preferred Properties: The diameter of pore of zeolite is 0.5-2 nm. The supporting rate of the metals other than aluminum ion is 0.1-5%.Preferred Method: After removing excess ion, baking process and reduction process are performed immediately.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The complex oxide contains at least 1 ion containing gold, platinum, or palladium in ion exchange site, in addition to aluminum ion. The oxidation state of supported gold, platinum, or palladium is zero when the ion containing gold, platinum, or palladium is decomposed and reduced. The oxidation number of supported silver, copper, manganese, cobalt, or iron is 1 or more, when the ion containing silver, copper, manganese, cobalt, or iron is decomposed. The complex oxide contains ion which contains titanium in ion exchange site, in addition to aluminum ion. The oxidation number of the supported titanium is 4 when the ion containing titanium is decomposed. The ratio of silica and alumina is 100 or less. The complex oxide is zeolite.Preferred Properties: The diameter of pore of zeolite is 0.5-2 nm. The supporting rate of the metals other than aluminum ion is 0.1-5%.Preferred Method: After removing excess ion, baking process and reduction process are performed immediately. EXAMPLE - Silica alumina complex oxide having ratio of silica and alumina of 40, was immersed to nona-hydrated aluminum nitrate aqueous solution and filtered. The complex oxide was washed, dried at 100degreesC, then immersed in tetramine platinum (II) dichloride aqueous solution, filtered and water washed. The oxide was dried at 100degreesC and catalyst was prepared. The obtained platinum catalyst had high activity with respect to methyl sulfide.