PROBLEM TO BE SOLVED: To provide a coating composition which enables a charge transfer type catalyst-containing coating film to be easily formed only by being applied to the base material and dried at low temperature and which enables durability of the coating film to be improved, and can give antifouling properties, antibacterial properties and deodorant properties and to provide a surface-treated base material obtained by applying the coating composition to the surface of the base material.SOLUTION: A coating composition containing low temperature-curable charge transfer type catalyst contains: (I) the charge transfer type catalyst; (II) an organosilicon compound; and (III) water and/or water-containing solvent. The organosilicon compound is obtained by hydrolyzing hydrolyzable silane (A) containing nitrogen atom containing organic group shown by formula: YRSiR(1) (wherein Ris a monovalent hydrocarbon group; Ris an alkoxy or acyloxy group; Y is a nitrogen atom-containing organic group; m is 0 or 1) and/or a
