The present invention relates to a three-dimensional forming method for a resin packaging material. By heating the resin packaging material to a temperature at or below the Vicat softening temperature of the packaging material and then compression molding at room temperature to a temperature at or below said Vicat softening temperature: molding load is reduced and equipment load is low even when forming a three-dimensional molded section with a large protrusion magnitude; productivity is excellent; residual stress of the three-dimensional molded section after forming is reduced; and even when contents are hot-filled, the molded height of the three-dimensional molded section is not reduced or reduction can be limited.
