PROBLEM TO BE SOLVED: To provide a method for producing a packaging material having high barrier property.SOLUTION: There is provided a method for producing a packaging material which comprises: heating a laminated film in which a sealant film is laminated on a barrier film including a barrier laminate including a substrate film, at least one organic layer and at least one inorganic layer and melting the sealant film, wherein a laminated film satisfying the following expression (I) is used as the laminated film: (I) X