Electronic blackboard

An electronic blackboard having a copy function, and an edit function or communication function. A single reading unit is used in common for both reading an image on a flat board and reading an image or an original document. Reflected light from the flat board and from the original document is converged and projected onto a light receiving surface of a single photoelectric conversion element. An image of the flat board of the original document can be selectively read, or the composite image of both the flat board and original document can be read. Further, the electrical signal corresponding to the image can be modulated and transmitted, and a received electrical signal can be demodulated to reproduce a corresponding image. Furthermore, in accordance with the electrical signal obtained by photoelectrically converting an image, the layout of the image on the flat board can be determined and edited to change the shape of the image.