In the packaging materials of the invention, a pair of inflation film layers is joined to each other by blocking in a flexible state to some degree without using adhesive. Therefore, they are not always joined completely integrally, and little space remains between the inflation film layers. The space can be increased by controlling the properties of the inflation film layers, blocking conditions and the like. By this pseudo-adhesion, physical strength such as tear strength is improved, buffer action is imparted, and curling is prevented.