PROBLEM TO BE SOLVED: To provide a container-packed milk-containing beverage having a good taste with a good balance between the taste derived from tea and the rich taste and moderate and soft acidity derived from milk components and a method for improving the taste of a container-packed milk-containing beverage.SOLUTION: The container-packed milk-containing beverage includes polyphenol in an amount of 0.045 to 0.105 g/100 g, having an acidity of 0.03 to 0.1 and a lactic acid content of 5 to 90% at the acidity. The method for improving the taste of a container-packed milk-containing beverage includes adjusting the amount of polyphenol to 0.045 to 0.105 g/100 g, the acidity to 0.03 to 0.1 g/100 g, and a lactic acid content to 5 to 90% at the acidity.
