A polyester film has a wax on a surface of one side of the film and is a polyester film in which this wax is dispersed in the form of islands on the surface of the film, and a filling factor of the wax in the film surface is 20 to 45%, and, as for a number of islands of the wax dispersed in the form of islands and each of which has an area of 200 μm2 or larger, there is one or less/10000 μm2.