a safety apparatus for use with a mechanized filing cabinet is provided. The safety apparatus comprises an upper bar and a lower bar. Each bar has a light-detecting element mounted on one end and a lamp mounted on the other end. The upper bar is springably attached to the lower edge of the door of the filing cabinet and the lower bar is springably attached to the rear edge of the posting board. The light-detecting elements are connected to the tray movement motor in such a manner. that the motor cannot be energized when the light beam impinging on either light-detecting elements is broken.