positioned the second positioning portion is positioned then a variation of an operating force when the accommodating unit 220 is mounted in the body unit 210 may be reduced when the transport device 200 is replenished with sheets pas recording mediums a handle portion 224 a of the front cover 224 is operated to move the accommodating unit 220 from the body unit 210 in the direction of the arrow r 2 see fig1 such that a sheet bundle is stacked on the sheet stacking plate bp in a state where the sheet stacking plate bp is exposed after the sheets pare stacked on the sheet stacking plate bp the handle portion 224 a of the front cover 224 is operated so that the accommodating unit 220 is moved in the direction of the arrow r 1 to be mounted in the body unit 210 the accommodating unit 220 is a box shape tray in its entirety which is entirely composed of the bottom plate 221 the side plates 222 and 223 the front cover 224 and the back plate 225 which are made of a synthetic resin material and is lighter as a whole as compared to one made of a metal meanwhile.