A paperboard shaped into a profile substantially the same as that of a carton blank for folding into a carbon is formed with a plurality of first slits on an edge of the paperboard at a predetermined angle relative to the edge and with a plurality of second slits on the same edge at a predetermined angle relative to the first slits in such a manner that saw-teeth are integrally formed thereon. The saw-teeth are immersed in a bath of a quick drying adhesive including .alpha.-cyanoacrylate to be impregnated with the adhesive and then dried, thereby forming teeth constituting a cutter on the carton blank. The carton obtained by folding the carton blank can be used as a packaging container for accommodating a roll of wrapping web. An apparatus for carrying out the method comprises a first group of cutting blades for forming the first slits, a second group of cutting blades for forming the second slits so as to integrally form saw-teeth on the edge portion, a bath of adhesive for impregnating the teeth with the adhesive, a dryer for drying the teeth, and a transfer device for transferring the paperboard along a predetermined path via the first and second groups of cutting blades, the bath and the dryer.