The invention provides a heat-shrinkable polyester film which has sufficient heat shrinkage properties in the main shrinkage direction that is the longitudinal direction without containing a monomer component that can form an amorphous component in a large amount, and which has a low heat shrinkage and a low shrinkage stress in the width direction orthogonal to the main shrinkage direction. The film has a heat shrinkage of 15-50% in a main shrinkage direction of the film and 0-12% in a direction orthogonal to the main shrinkage direction of the film, when treated for 10 seconds in hot water of 90 C., and a maximum shrinkage stress of 2-10 MPa in the main shrinkage direction of the film when measured under hot air of 90 C. The film contains 7-30 mol % of a constituent unit derived from diethylene glycol in 100 mol % of the whole polyester resin component.

The invention provides a heat-shrinkable polyester film which has sufficient heat shrinkage properties in the main shrinkage direction that is the longitudinal direction without containing a monomer component that can form an amorphous component in a large amount, and which has a low heat shrinkage and a low shrinkage stress in the width direction orthogonal to the main shrinkage direction. The film has a heat shrinkage of 15-50% in a main shrinkage direction of the film and 0-12% in a direction orthogonal to the main shrinkage direction of the film, when treated for 10 seconds in hot water of 90 C., and a maximum shrinkage stress of 2-10 MPa in the main shrinkage direction of the film when measured under hot air of 90 C. The film contains 7-30 mol % of a constituent unit derived from diethylene glycol in 100 mol % of the whole polyester resin component.