PURPOSE: To move a capsule without need for large drive power, by means of vibratory motion of a flexible pipe.

CONSTITUTION: A flexible pipe 3 is provided with a pipe wall exciting means 9 to move peristaltically. A capsule 1 fitted to a guide rail 19 installed along the longitudinal axis line of the flexible pipe 3 is moved by unstable fluid force. When the capsule, 1 slows down, it is accelerated again by peristaltic motion of the flexible pipe used as a booster. The capsule 1 can be decelerated by providing the flexible pipe with peristaltic motion which differs in phase by 180 degrees. As mentioned above, the capsule 1 can be moved by peristaltic motion of the flexible pipe 3, without need for a large drive power such as compressed air.