The purpose of the present invention is to provide a fatigue ameliorating agent which does not require prolonged intake of a large amount of a liquid and can be taken without a burden. The fatigue ameliorating agent comprises, as an active ingredient, an emulsified composition containing a milk protein mixture containing casein protein and whey protein, wherein the concentration of the milk protein mixture in the emulsified composition is 4-8 wt% and the mass ratio of the casein protein to the whey protein (casein protein/whey protein) is 2-20. When taken in a daily dose of, for example, 100-500 ml for 2-8 weeks, the fatigue ameliorating agent exerts a fatigue ameliorating effect.本發明之目的係提供一種疲勞改善劑，其係為不需多量且不需長時間攝取液體，且這種攝取本身沒有負擔之疲勞改善劑，其係包含：將具有酪蛋白質與乳清蛋白質之乳蛋白質混合物的乳性液狀組成物作為有效成分之疲勞改善劑，其中，該乳性液狀組成物中該乳蛋白質混合物之濃度為4~8重量%，且乳清蛋白質相對於酪蛋白質之蛋白質量比(酪蛋白質/乳清蛋白質)為2~20。例如以一日份量為100~500ml攝取此疲勞改善劑2~8週，即產生疲勞改善之效果。
