PURPOSE: To provide the driving member of a conveying device allowing an inside magnet device to freely move inside a curvedly arranged conduit and capable of sufficiently exerting the magnetic coupling function between the inside magnet device and an outside magnet device for reliable conveyance.

CONSTITUTION: A driving member 2 having an inside magnet device 3 traveled by a pressure fluid in a conduit made of a nonmagnetic material is provided, a driven member 10 having an outside magnet device 11 corresponding to the inside magnet device 3 of the driving member 2 is slidably provided outside the conduit 1, a support device of a conveyance object is provided on the driven member 10 of a conveying device, and magnets of the inside magnet device 3 of the driving member 2 are supported by flexible shafts respectively.