There is provided a gas barrier clear film 10 as a polymer substrate that is flexible, is light, is free from cracking, can be bent, has a high level of heat resistance, is excellent particularly in gas shielding properties, and can be used as an alternative to glass substrates.The gas barrier clear film comprises: a clear resin base material film 11 having a coefficient of linear expansion of 15 to 100 ppm/K and a glass transition temperature Tg of 150 to 300.degree. C.; and a first clear inorganic compound layer 13A, a sol-gel coat layer 15A, and a second clear inorganic compound layer 13B provided in that order on the clear resin base material film 11. The second clear inorganic compound layer 13B has an Ra (average roughness) value of not more than 5 nm and an Rmax (maximum roughness) value of not more than 80 nm.