The present invention provides as steam barrier resin, a steam barrier coating agent, a steam barrier film, and a steam barrier laminate that exhibit an improved steam barrier property. The steam barrier resin is obtained by reacting a carboxylic acid group and/or an acid anhydride group of a copolymer (C) with an organometallic complex (D). The copolymer (C) is obtained by polymerizing an unsaturated hydrocarbon monomer (A) and an unsaturated carboxylic acid and/or an unsaturated dicarboxylic anhydride (B). Further, the steam barrier resin includes metal bridging between the copolymers (C). The steam barrier coating agent contains the steam barrier resin and a solvent (B). The steam barrier film of the present invention is a film containing the steam barrier. The steam barrier laminate is obtained by laminating the steam barrier film of the present invention on at least one surface of a substrate film.