To provide a polyester film which is useful as the base film for a releasing film and has excellent properties such that, when a ceramic slurry is placed on the releasing film, the irregularities in the thickness of the placed ceramic layer are remarkably reduced and, simultaneously, the formation of pinholes in the ceramic slurry layer can be inhibited.

The polyester film for a releasing film is characterized in that it has a tensile modulus (EMD) in the film lengthwise direction of ≥4.0 GPa.