The present invention provides a resin composition of a saponified ethylene-vinyl ester copolymer can provide a molded product including layer of the resin composition with less thickness variation and excellent gas-barrier properties, even if the layer is subjected to stretch forming such as deep drawing forming and vacuum-pressure forming where the layer is applied with different tension from side to side thereof in short time. The resin composition comprises an EVOH resin having ethylene content of 20 to 60 mol % and a PVA having 1,2-diol structural unit in a side chain. The present invention also provides a multilayer structure using the resin composition.