An image reading apparatus includes a first reading element for receiving visible light in reflected light from a color document and reading image data corresponding to the visible light as electric signals, and a second reading element for receiving infrared light in reflected light from the color document and reading image data corresponding to the infrared light as electric signals. The image reading apparatus thus reads the image data not only from the visible light but also from the infrared light. Consequently, the image reading apparatus is capable of reading a special distinguishing pattern of copy-prohibited printed matter printed with special ink, such as infrared absorbing ink, as well as ordinary image data, and thereby preventing counterfeiting of copy-prohibited printed matter.