PROBLEM TO BE SOLVED: To provide a flavor improver capable of improving the flavor of polyunsaturated fatty acid-containing fat over a long period, a composition containing the flavor improver, food and drink, a pharmaceutical composition or a cosmetic containing the flavor improver or the composition, and a method for improving the flavor of polyunsaturated fatty acid-containing fat.SOLUTION: Provided is a flavor improver for polyunsaturated fatty acid-containing fat containing basic peptide, preferably one or more kinds selected from the group consisting of polylysine, polyarginine, polyhistidine, histone and protamine, and also provided is a polyunsaturated fatty acid-containing fat composition containing fat including polyunsaturated fatty acid and the basic peptide.
