The invention relates to a method for the automatic production of bags (9) that are equipped with a sealing device (3). Said method comprises the following steps: provision (P) of at least one web of plastic film (1), provision of a sealing device (3), fixing of the sealing device (3) to the web of plastic film (1) and welding (7, 8) of the web of plastic film (1) to form bags (9). According to said method, the plastic-film web (1) is perforated (2) at a distance from its edge (5) prior to the provision (P) of the sealing device (3) and the complementary sealing profile (3) is fixed to the web of plastic film (1) directly over the perforation. The bag (9) is then formed and welded by means of at least one longitudinal (7) and/or transversal weld (8).