Provided is a sheet (2) for forming protective film, including: a protective film-forming film (1) characterized in that the light transmittance thereof at a wavelength of 1600 nm of 72% or more, and the light transmittance thereof at a wavelength of 550 nm of 20% or less; and a release sheet (21) laminated upon one or both faces of the protective film-forming film (1). According to this sheet (2) for forming a protective film, it is possible to form a protective film that allows for the inspection of cracks, etc., on a workpiece or a product obtained by processing the workpiece, while preventing grinding marks on the workpiece or the product from being visible to the naked eye.