To provide a which polyester film useful for IC card substrates which has high reliability, especially reduce the frequency of data error generation due to IR light, and has excellent designability and excellent productivity.

This white polyester film having a thickness of 50 to 250 μm and comprising a polyethylene terephthalate composition containing particles having an average particle diameter of 0.1 to 5.0 μm in an amount of 20 to 40 wt.%, is characterized by having a surface glossiness of 10 to 50%, an IR light transmittance of 0.1 to 20% and an X-ray diffraction intensity ratio satisfying the following expression (1): 0.08≤I (11'0)/I(100)≤0.15... (1) [I (11'0) is an X-ray diffraction intensity on the surface (11'0) parallel to the surface of the film; I (100) is an X-ray diffraction intensity on the surface (100) parallel to the surface of the film and each 1' is to be expressed by 1 with a short bar on its top].