PURPOSE: To provide a photo-plotter not requiring any synchronizing device or any driving device, provided with light-emitting elements for individually giving a dot light group to the entire region of an image and a group of optical fibers proximately faced to the elements.

CONSTITUTION: A light exposure head is constituted of a light-receiving part 2, an optical fiber cable 3, a light-emitting part 4 and the like. Input ends of the fibers in the cable 3 are arranged in a matrix form and fixedly contained in a fitting frame to constitute the light-receiving part 2, while the light-emitting part 4 faced thereto consists of a group of light-emitting elements such as light- emitting diodes arranged at the same pitch as that of the fiber matrix in the light-receiving part 2. Dot image data DD covering the entire region of a layout pattern to be formed on a printed substrate 5 cause the light-emitting diodes at respective positions to emit light, the resultant output is led to the tips of glass fibers provided in the head 1 through the light-receiving part 2 and the cable 3, and the substrate 5 faced thereto is exposed to light at corresponding positions.