PURPOSE: To prevent waste of paper and cutting of the paper at the position off the perforations in a printer device of a computer system, by cutting the paper along the perforations through detecting the perforations of a continuous form and setting the perforations to a specified position.

CONSTITUTION: A leading part of a continuous form for a printer is set so as to be fitted to a pin feeder 2, and then the form is fixed by means of the pin feeders 2 and 3. A scored line detecting part 4 measures number of rotation of the pin feeders 2 and 3 with respect to the initial position where the leading part of the form has been set to the pin feeder 2. The printer is controlled so that the perforations 11 comes to the position under a perforations cutting part 1 after this measured data has been output. Consequently, after the outputting of this measured data has been finished, the perforations 11 stops under the dull blade 10 of the perforations cutting part 1. At this position, an end part B of the perforations cutting part 1 is lifted upwards by hand, and the form is cut by the returning motion of the blade 10 after releasing of the hand.