Abstract: A continuous paper sheet has a plurality of transversal perforation lines and a plurality of holes formed in the longitudinal margins of the paper sheet. The paper sheet is torn by two pairs of nipping rollers including a pair of upper and lower feed-in rollers and another pair of upper and lower pulling rollers. The pulling rollers of the latter pair rotate at a speed higher than that of the feed-in rollers so that the part of the sheet placed between the former pair of rollers and the latter pair of rollers is pulled or given tension, thus being torn and separated. After it has been confirmed the continuous paper sheet has been placed on a stand at a predetermined position, the length of the continuous paper sheet as folded is measured. The resultant measurement is compared to standard sizes previously inputted to a CPU in order to correct it to the approximate standard size.