The invention provides a heat-shrinkable polyester film, which has a main shrinkage direction in a longer direction, exhibits a higher shrinkage ratio in the main shrinkage direction, has small difference in shrinkage ratio at a high temperature and a low temperature so as not likely to generate wrinkles or the like when being used as a label, and exhibits small over-time decrease in shrinkage ratio at a low temperature. The heat-shrinkable polyester film has, as a main component, ethyleneterephthalate, and an amount of a diethyleneglycol (DEG) component is 10-25 mol % with respect to 100 mol % of a polyhydric alcohol component in all of polyester resin that composes the film.