The gas-barrier film of the present invention basically comprises a polymer of a polyvalent metal salt of an unsaturated carboxylic acid compound which gives an infrared absorption spectrum in which the ratio of the absorbance A0 at around 1,700 cm−1 attributable to V C═O of the carboxylic acid group to the absorbance A at around 1,520 cm−1 attributable to V C═O of the carboxylate ion, A0/A, is lower than 0.25, and this gas-barrier film and a gas-barrier layered body having the film can be manufactured by applying a solution of a polyvalent metal salt of an unsaturated carboxylic acid compound having a degree of polymerization lower than 20 to at least one side of a substrate layer and then polymerizing the polyvalent metal salt of the unsaturated carboxylic acid compound.