An overtube including an insertion portion having a distal end portion and a proximal end portion, at least the distal end portion being inserted into an examination subject a first lumen formed in the insertion portion and in which a device for carrying out medical procedures in the examination subject is freely inserted and removed a tissue cutting portion that is to be disposed at the distal end portion of the insertion portion traversing the first lumen and that cuts the tissue of the examination subject and a holding portion that holds the tissue cutting portion at a position removed from a position traversing the first lumen.
