Abstract: An optical apparatus having a base table on which an original is placed and an image forming unit with an optical system which projects an image of the original onto a remote screen for showing the same to a number of viewers. A foldable structure is provided, having a support structure mounted on a base table for movement between a lowered position covering the base table and a raised position wherein the image forming unit is located above the base table so as to form and project the image of the original onto the remote screen. A linkage interconnects the image forming unit and the support structure for causing a movement of the image forming unit relative to the support structure upon movement of the support structure between the folded and unfolded positions, thereby placing the image forming unit above the base table when the supporting means is in the raised position and flush with the support means so as to cover the base table when the support means is in the lowered position.