Abstract: A printing device reads an image on a printing paper with an image pickup part. It image-processes obtained image data in a control part, and operates the positions of respective register marks (R1 to R4). It operates the quantity of displacement necessary for positioning an image. It obtains an offset count number Co for deciding an image recording starting position from the obtained quantity of displacement. It stores the obtained offset count number Co while obtaining starting position data. Then, dimensional correction data for the image is calculated. The image on the printing paper is first picked up, and the necessary quantity of displacement is calculated. A speed coefficient k is calculated for changing the rotational speed of a plate cylinder. Following this, a correction quantity by a Cd default count number previously set for deciding the image recording starting position is changed. Accordingly, the offset count number Co is calculated again on the basis of the obtained speed variable k.