A tray unit having a tray that is open at the top and a card holder mounted to the outer peripheral face of the tray. The tray has a bottom face, an outer peripheral wall that rises upward from the outer peripheral part of the bottom face, and a flange extending from the upper face side of the outer peripheral wall in the outer peripheral direction. The card holder has a card insertion portion along the outer peripheral wall of the tray and to the outside of the outer peripheral wall, and to which a card is removably inserted, and a guide portion that is provided at the upper part of the card insertion portion and has formed thereon a sloped face that increases in height from the outer peripheral wall of the tray in the outer peripheral direction of the tray.