A bag maker bends an elongate bag-forming film (f) into a tubular shape, moves it longitudinally along a path, seals its mutually overlapping side edges into a tubular shape, fills it with articles to be packaged and simultaneously seals it transversely with a transverse sealer (110) to make individual filled bags. The transverse sealer (110) has a pair of seal jaws (21) opposite each other across the path of the film, each adapted to move in a D-shaped closed trajectory and inwardly towards each other to transversely seal the film over a seal area. A pair of shutters (30) is disposed on the seal jaws (21) so as to each move behind corresponding one of the seal jaws when moving downward. These shutters (30) are biased towards each other and normally protrude inwardly from the inward-facing surfaces of the seal jaws so as to prevent articles intended for the next bag to be produced will not be caught between the seal jaws when transverse sealing is effected. The shutters have inwardly facing surfaces each having protrusions (32) and indentations (33) alternately arranged transversely. The protrusions on one side of the shutters each face corresponding one of the indentations on the other shutter with a gap therebetween when they are pushed towards each other. <IMAGE>
