Exhaust gas purifying catalyst having excellent silicon tolerance

To provide a catalyst composition having excellent silicon resistance and a catalyst that contains the catalyst composition. A catalyst composition for purifying an exhaust gas containing an organic compound, which contains: (component 1) at least one inorganic oxide that is selected from the group consisting of alumina, zirconia, titania, silica, ceria and ceria/zirconia, each of which is loaded with a noble metal; (component 2) a β-zeolite that is loaded with at least one metal selected from the group consisting of Fe, Cu, Co and Ni; and (component 3) a Pt-Fe composite oxide.