<;P>;PROBLEM TO BE SOLVED: To provide an oil deterioration preventive agent having excellent oil deterioration preventive action. <;P>;SOLUTION: The oil deterioration preventive agent comprises a compound having active oxygen scavenging activity with IC50 values of &le;10,000 ppm and a film-forming agent having dispersibility into water and a surface tension of &le;40 mN/m under the condition of 25°;C. <;P>;COPYRIGHT: (C)2009,JPO&INPIT