The direction-turning function and the function for getting over an obstacle are enhanced in self-propelling of an elongated cable having a relatively small flexural rigidity. A predetermined bend (6a) is provided in at least the tip region (6) of a cable (1) and a propulsion unit being shaken by vibration to produce a driving force in a predetermined direction is arranged on the outside of the cable (1). The cable (1) is shaken by a shaker consisting of an electric motor (3) and a lever crank mechanism (4), and the cable (1) is propelled with the driving force of the propulsion unit (11). Traveling direction at the tip of the cable (1) is changed by turning the cable (1) in the axial direction to change the direction of the bend.
