NOVELTY - A gas-barrier multilayer film has a gas-barrier layer obtained by hardening polyester resin composition formed by reacting polyester polyol and hardening agent. The polyester resin composition is polyester resin composition (c1) formed by reacting polyester polyol (I) and a hardening agent, oxygen-barrier adhesive-agent resin composition (c2) formed by reacting polyester polyol (a) having polymerizable carbon-carbon double bond and polyisocyanate (b) or oxygen-barrier adhesive-agent resin composition (c3) containing polyester polyol (c) and polyisocyanate (d).    USE - Gas-barrier multilayer film is used for material for packaging (claimed) foodstuffs and drink. Uses include but are not limited to electronic material, display element, building material, primer of film laminate, protective film of solar cell and sealing material of display element.    ADVANTAGE - The multilayer film has excellent gas-barrier property.    DETAILED DESCRIPTION - A gas-barrier multilayer film has a gas-barrier layer obtained by hardening polyester resin composition formed by reacting polyester polyol and a hardening agent. The polyester resin composition is polyester resin composition (c1) formed by reacting polyester polyol of formula (I) and a hardening agent, oxygen-barrier adhesive-agent resin composition (c2) formed by reacting polyester polyol (a) having polymerizable carbon-carbon double bond in molecule and 2 or more hydroxyl groups and polyisocyanate (b) having 2 or more isocyanate groups or oxygen-barrier adhesive-agent resin composition (c3) containing polyester polyol (c) and polyisocyanate (d) having 2 or more isocyanate groups. The polyester polyol (c) has at least one carboxyl group and 2 or more hydroxyl groups obtained by reacting carboxylic anhydride or polyhydric carboxylic acid with polyester polyol having 3 or more hydroxyl groups.    R1-R3=H or -(C(=O)-X-C(=O)-O-Y'-O)n-H, where at least one of R1-R3 is or -(C(=O)-X-C(=O)-O-Y'-O)n-H;    n=1-5;    X=optionally substituted 1,2-phenylene, 1,2-naphthylene, 2,3-naphthylene, 2,3-anthraquinone diyl or 2,3-anthracenediyl;and    Y'=2-6C alkylene.    INDEPENDENT CLAIMS are included for the following:    (1) non-solvent-type gas-barrier coating material; and    (2) non-solvent-type gas-barrier adhesive agent.