A recorded image is distorted on a printing plate when an image information for a computer is recorded in the form of a band with a band width of a plurality of image elements on a printing plate wound around a drum. This invention provides an undistorted recording on the printing plate, made possible by an arrangement that has a printing plate wound around a drum in the form of a right circular cylinder, an exposure unit that uses a light beam to record image information in the form of a band on the printing plate, a moving mechanism to move the exposure unit by one band width in the direction of the drum axis in relation to the drum while the drum makes a revolution, an image treating apparatus with the image information stored in the form of a right quadrangle, and an image modulator to rearrange and slant each band of image information readout from said image treatment apparatus by one band width in the opposite direction to the movement of said moving mechanism.