To provide a simple and environmentally friendly method for peeling a protective film applied on matter to be processed.

The method for peeling a protective film comprises forming a protective film composed of a curable composition on the surface of matter to be processed, processing the matter to be processed and subsequently peeling the protective film from the matter to be processed, where a sheet is pasted on the surface of the matter to be processed and/or the surface of the protective film and then separating the matter to be processed from the protective film and the sheet or separating the protective film from the matter to be processed and the sheet. Preferably, at least the protective film is brought into contact with warm water on peeling. More preferably, the sheet pasted on the surface of the matter to be processed and/or the surface of the protective film is a pressure-sensitive adhesive sheet comprising a substrate and a pressure-sensitive adhesive layer formed thereon.