It is an object of the present invention to provide a release film which is superior in the flexibility at high temperature, the conformability to circuit patterns, the heat resistance, the releasing property and the non-contaminative property, and easily discarded after use.The present invention relates to a release film, which is used in a manufacturing process of a printed-circuit board, a flexible printed-circuit board or a multilayer printed-circuit board, having a layer comprising a resin composition comprising a resin having a polar group in a main chain as a matrix and having a halogen content of 5% by weight or less on at least one surface.