A portioning device is provided for forming portions from elongate casings stuffed with food mass, in particular for forming sausages from alginate casings stuffed with sausage meat. The portioning device includes two circulating conveyor members spaced apart from one another and drivable by at least one drive element, and at least one crimping member arranged on each conveyor member and projecting laterally from the conveyor member. It is proposed that at least one of the crimping members has such a shape, on its functional area that in the conveying area at least partially faces an opposite crimping member, that corrugations, creases and/or folds extending substantially parallel to the conveying direction, in particular, are formed in the constricted portion of the casing, thereby producing a desirable shape for the portions separated.