A surface substrate film for an automobile brake disc anti-rust film, which has a tensile modulus of 220 MPa or more; and the surface substrate film which optionally contains 0.01 to 20 parts by mass of an ultraviolet ray absorbing agent relative to 100 parts by mass of the surface substrate film in a manner such that a spectral transmittance in a wavelength region of 200 to 380 nm becomes 0 to 20 %. The above surface substrate film for an automobile brake disc anti-rust film is less susceptible to falling off when pasted on a wheel of an automobile. |