Form-fill-seal machine includes parts for moving a web of packaging material through the machine according to a process path and parts for transforming the web into filled bags, as well as a zipper strip applicator device for supplying a zipper strip for each bag transverse to the process path, by use of a first and a second conveyor, which in the supply direction of the zipper strip are placed one behind the other and are both provided with parts for retaining the zipper strip during supply, a blade being placed between the first and the second conveyor for cutting the zipper strip and the first and the second conveyor being provided with their own first and second drive.