Packaging machine for packaging paper rolls, including an operating group forming packages, with an entrance station for the rolls and the packaging sheets, and an output station for the packaged rolls; an elevator; a structure on which the operating group is mounted; a plane on which a folder and a counter-folder are formed for folding the packaging sheets under the rolls; a conveyor for moving the packages being formed above said plane; means for welding the packaging sheets; a welding bar for welding the packaging sheets under the rolls. The welding bar is configured to come out through an opening made on the counter-folder and reposition itself below the latter. The carriages are controlled independently of each other.