An image forming device includes an image forming device body having an image forming unit in the interior thereof, and at least one paper tray attached to the image forming device on which paper is to be mounted. The paper tray includes a paper mounting unit having a paper mounting surface on which paper is to be mounted, and at least one movable auxiliary mounting unit. The auxiliary mounting unit is supported by the paper mounting unit, and includes an auxiliary mounting surface that is deployed from the paper mounting unit and which serves to extend the mounting surface. The brightnesses of the mounting surface and the auxiliary mounting surface of the paper tray are lower than the brightness of the paper to be mounted on each mounting surface, and the brightness of at least a portion of the auxiliary mounting surface is higher than the brightness of the mounting surface.