A positioning apparatus comprising: an apparatus body ; a draw-out portion configured to be drawn out from and attached to the apparatus body ; and a positioning mechanism configured to position the draw-out portion at an attachment position with respect to the apparatus body , wherein the positioning mechanism comprises: a first engaging portion provided in one of the apparatus body and the draw-out portion ; and a first engaged portion provided in another of the apparatus body and the draw-out portion and configured to determine a position of the draw-out portion in an attachment direction (Y1) by engaging with the first engaging portion , the first engaged portion including an inclined surface and a positioning surface , the inclined surface being configured to contact the first engaging portion , the positioning surface being configured to position the draw-out portion in the attachment direction (Y1) at the attachment position, and characterized in that the inclined surface is inclined downward toward a downstream side in the attachment direction (Y1) and causes a component force (F2) in the attachment direction (Y1) to act on the draw-out portion on a basis of a weight of the draw-out portion such that the positioning surface is pressed against the first engaging portion in a state in which the inclined surface contacts the first engaging portion . an apparatus body ; a draw-out portion configured to be drawn out from and attached to the apparatus body ; and a positioning mechanism configured to position the draw-out portion at an attachment position with respect to the apparatus body , wherein the positioning mechanism comprises: a first engaging portion provided in one of the apparatus body and the draw-out portion ; and a first engaged portion provided in another of the apparatus body and the draw-out portion and configured to determine a position of the draw-out portion in an attachment direction (Y1) by engaging with the first engaging portion , the first engaged portion including an inclined surface and a positioning surface , the inclined surface being configured to contact the first engaging portion , the positioning surface being configured to position the draw-out portion in the attachment direction (Y1) at the attachment position, and a first engaging portion provided in one of the apparatus body and the draw-out portion ; and a first engaged portion provided in another of the apparatus body and the draw-out portion and configured to determine a position of the draw-out portion in an attachment direction (Y1) by engaging with the first engaging portion , the first engaged portion including an inclined surface and a positioning surface , the inclined surface being configured to contact the first engaging portion , the positioning surface being configured to position the draw-out portion in the attachment direction (Y1) at the attachment position, and characterized in that the inclined surface is inclined downward toward a downstream side in the attachment direction (Y1) and causes a component force (F2) in the attachment direction (Y1) to act on the draw-out portion on a basis of a weight of the draw-out portion such that the positioning surface is pressed against the first engaging portion in a state in which the inclined surface contacts the first engaging portion . <EOS>