An endoscopic overtube includes a tube body having a first lumen for insertion of an insertion part of an endoscope a shape-changeable pinching part capable of coming into contact with an outer surface of the insertion part inside the first lumen and holding the insertion part by coming into contact with the outer surface of the insertion part to position the insertion part in the first lumen and a manipulation part attached to the tube body. The manipulation part is connected to an end portion of the tube body to be rotatable with respect to the tube body, and switches by a rotational motion between a pinched state in which the insertion part is positioned with respect to the first lumen by the pinching part and an open state in which the insertion part can advance, retract, and rotate in the first lumen.
