A body-insertable apparatus comprising: a tube sized to receive visualization apparatus disposed within a lumen of the tube a 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 thread a pressure applying section that applies pressure to the filling material in the helical thread and a 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.
