To improve heat sealability together with gas barrier properties by laminating a polyobutylene terephthalate resin layer having a specific flexural moduls as a sealant layer on a base material film via an adhesive layer, thereby eliminating an odor transfer of a retort packaging material to a content.

A polybutylene terephthalate(PBT) resin layer 12 having a flexural modulus of 3,000 to 13,000 kg/cm2 is laminated on a base material film 11 via an adhesive layer 13. As the film 11, a PET film, an ONy film, or a laminar or multilayer film of Al or the like is preferably used. As the layer 12, specifically, a NOVADUR 5500 series (made of MITSUBISHI Engineering Plastic Co., Ltd.) is used. As the layer 13, a two-component reaction type polyester adhesive is preferably used. And, this corresponds to an adhesive layer in the case of laminating the film 11 and the layer 12 preferably by a dry laminating process.