The invention relates to a method for ultrasound welding of two bag foils to a spout, wherein at a first method step, a lateral edge of a bag foil abutting the spout is welded to the spout with a first oscillating structure, at a second method step, the lateral edge of the second bag foil abutting the opposite side of the spout is welded to the spout with a second oscillating structure, and at a third method step, the lateral edges of the two bag foils located next to the spout are welded to each other with a third oscillating structure.