PROBLEM TO BE SOLVED: To provide an intra-tract propulsion device continuously propelling a small apparatus such as an endoscope in a lumen such as the small intestine or a tract.SOLUTION: The intra-tract propulsion device includes a tube assembly formed by spirally winding a plurality of tubes mutually and tightly closing one ends of the respective tubes. Each of the plurality of tubes of the tube assembly includes the other end, which is in the opposite side of the closed one side, connected to a fluid pressure source. (1) A pressure is applied to one tube of the plurality of tubes, from the fluid pressure source (2) to reduce the pressure of the tube and a pressure is applied to another tube and (3) the steps of (1) and (2) are sequentially performed for all the tubes without any overlap till returning to the first tube such that (4) the tube assembly moves in the tract in the axial direction of the tract by repeating the steps of (1)-(3).
