The method for preventing the deterioration of a lubricating oil comprises measuring with time the peroxide value(POV) of a lubricating oil used in an oxidizing atmosphere, and adding an antioxidant to the oil to prevent the POV from exceeding 0 ppm, or when the POV exceeds 0 ppm, or to prevent the POV from exceeding 1 ppm.例文帳に追加 酸化雰囲気下で使用される潤滑油の過酸化物価(POV)を経時的に計測して、潤滑油のPOVが0ppmを超えないように、もしくは0ppmを超え