A gas barrier film, a display substrate and a display using the gas barrier film. The gas barrier film includes a base material film having a deflection temperature under load of 150.degree. C. or above, and at least a gas barrier layer and a smoothing layer in that order, or a smoothing layer and a gas barrier layer in that order provided on the base material film. Preferably, the base material film is polyethylene naphthalate, the gas barrier layer is formed of an inorganic oxide, an inorganic oxynitride, an inorganic oxycarbide, or an inorganic oxycarbonitride, and the smoothing layer formed of a cardo polymer, sol-gel, or a material containing an acryl structure.