A method for manufacturing a shielding film is provided. The method includes providing a band of an amorphous soft magnetic alloy; thermally treating the band at a temperature of 500° C. to 600° C. for 1 minute to 1 hour under an N2- or H2-containing atmosphere and under the Earth's magnetic field, thereby creating a nanocrystalline soft magnetic band with a round hysteresis loop; applying an adhesive layer to at least one side of the band; and wherein the band is first applied to a substrate, then thermally treated, after which an adhesive film is applied to the band and, finally, the band is structured by breaking.