A document reading device includes a document reading section, an image memory, and an image processing section. The image processing section is configured to retrieve an image of an original document from the image memory and process the image. The image processing section includes: a mark recognizing section configured to recognize an image of a predetermined mark made on the original document; a sticky note recognizing section configured to recognize an image of a sticky note placed on a predetermined position of the original document relative to the mark; a mask determining section configured to determine in which mask pattern the mark is masked with the sticky note; and an image manipulating section configured to manipulate the image of the sticky note according to the mask pattern determined by the mask determining section.