Abstract: A method for forming aggregates of food pieces by arranging a plurality of food pieces such that the food pieces at least partially overlap one another is provided. The method automatically changes the number of food pieces forming each aggregate and a pitch at which the food pieces are arranged so as to limit the weights of the aggregates within a predetermined permissible range and to form each aggregate such that the total length of the aggregate is a preset length. The method also automatically changes the number of food pieces forming each aggregate and the pitch at which the food pieces are arranged according to the length of the food piece in the arrangement direction.