Abstract: A device including a shaping member having a female part that includes a recessed region fastened to means for translation along a first direction, and provided near its edges with suckers, which are intended to receive a sheet of flexible material. The female part also includes a jaw hinged to its edges, which defines, with the recessed region, a desired shape of an envelope of a package to be produced. A male sleeve or mandrel, complementary in shape to the internal shape of the female part and capable of undergoing a translational movement in a direction perpendicular to the first direction, is also provided. The male part is positioned level with, and cooperates with, the female part. A member for fastening together the two edges of the sheet of flexible material after shaping is also provided.