The invention relates to a window transparent to electron rays comprising a foil (1, 10, 300a) transparent to electron rays and separated from a carrier substrate as well as a retaining element (2, 300b) for supporting a peripheral region of the foil transparent to electron rays in the operational state, which retaining element (2, 300b) is made of a material which has a linear thermal expansion coefficient which matches the linear thermal expansion coefficient of the foil material. The invention further relates to a method of manufacturing a window transparent to electron rays and an X-ray device with such a window.