PURPOSE: To impart elongating and contracting properties and bendability to a sliding tube by adopting constitution to mount a plastic film of vinyl, rubber, etc., at the outer side of a spring.

CONSTITUTION: This sliding tube is constituted by forming a skeleton part as a spring-like part (spring 1) like a hose of a cleaning machine and mounting the plastic film 2, such as vinyl or rubber, at the outer side thereof. The spring 1 is usually held compressed by a compressing machine 3 and the sliding tube is successively inserted into the anus by gradually elongating the spring 1 at the time of insertion from the anus, by which the spring 1 is mounted in the extended state in the colon. As a result, the sliding tube having about an overall length of 20cm at the time of compressing is extended to 1 to 1.5m at the time of extending, by which the arrival of the sliding tube at the transverse mesocolon is made possible. Since the spring 1 and the film 2 of the sliding tube protect the colic wall, the insertion of the colon scope is facilitated.