A body-insertable apparatus comprising:a tube sized to receive visualization apparatus disposed within a lumen of the tubea helical thread provided on the outer periphery of the tube, the helical thread being rotatable with respect to the longitudinal axis of the tube and into which a filling material can be introduced, wherein the mechanical properties of the helical thread are varied by the filling material in the helical threada pressure applying section that applies pressure to the filling material in the helical thread anda filling material evacuating section that is provided in the helical thread and which is activated by application of pressure so as to evacuate filling material from the helical thread.
