PURPOSE: To form different-size bags and deposit each of them in a case of corresponding size by using integrated forming/filling/sealing packaging machine.

CONSTITUTION: A web of flexible packing material is fed from a tube-shaping shoulder section 3 downward along the surface of a mandrel 13. The lengthy edges of the web are overlapped each other and sealed in a tube form by a sealing device 15. The product of interest is weighed and supplied into the tube. A pair of sealing bars 17 seals the tube crosswise to form a bag filled with the weighed product. With the sealing bars released, a packaging conveyor assembly at a packaging station 14 drops the bag into carton C matching the size of the bag. The case is transferred from the packaging station 14 to a case ejection station and sealed at the upper end and the lower end.