A paper feeding device comprising a tray storing case attachable to and removable from a device housing; a rotatable tray, provided in the tray storing case, which rotates copy paper to a longitudinal and lateral feed position; and a mechanism for lifting up a paper-feed end of a paper holding plate provided in the tray when paper is to be fed. The mechanism is composed of a guide member provided in the device housing; a lift-up guide provided on a side face located on a paper-feed end of the tray; a first rotary bar provided in the tray storing case and driven by the guide member when the tray is attached thereon; and a second rotary bar, a spring and a lift plate driven by the lift-up guide when the tray is in the paper-feed position. The first and second bars are driven simultaneously, thus lifting up the paper-feed end of the paper holding plate. Alternatively, the mechanism comprises at least three springs provided between the tray and the tray storing case; a guide rib provided in the tray storing case; and a pivot pin, a wire and a slide plate provided on the paper holding plate. The guide rib causes the slide plate to rotate and the wire pulls the pivot pin downwards. A simplified and miniaturized mechanism that lifts up and lowers the paper holding plate is thus achieved.