PROBLEM TO BE SOLVED: To provide a carotenoid-containing composition which exhibits a useful effect for the skin, such as aging prevention, and prevention/amelioration of stains, while being excellent in stability of a carotenoid, and to provide a deterioration inhibitor, an external preparation for skin, a cosmetic preparation, and to provide a deterioration inhibition method of astaxanthin by the oil solution.SOLUTION: There are provided a composition characterized by containing an oil solution which has a carotenoid, such as astaxanthin having an antioxidant effect, an anti-inflammatory effect, a skin aging prevention effect, and a whitening effect, and a pentaerythritol backbone, such as tetra-2-ethyl hexanoic acid pentaerythrityl, and a deterioration inhibition method of a carotenoid by the oil solution.
