A monolayer polypropylene film obtained by melt extrusion from a composition comprising 100 parts by weight of a crystalline polypropylene and, incorporated therein, a slipping agent {A} having a melting point of 100.degree. to 125.degree. C. and a slipping agent {B} having a melting point of 70.degree. to 90.degree. C. in a total amount of 0.05 to 1.0 part by weight, the initial coefficient of friction of said film being 0.7 or below and the coefficient of friction after heating at 60.degree. C. being 1.0 or below; and a multilayer film composed of said polypropylene film layer having said composition and said characteristics and a substrate material layer.