The invention relates to a guide device (1), in particular for positioning catheters in a body duct. The guide device (1) has an extended first thread (2) and at least one extended second thread (3) made from wire, which runs close to the first thread (2). According to the invention, the guide device (1) has a device (8), provided for one of the threads (2, 3) by means of which it is possible to actively control a relative movement between the threads (2, 3) or at least make the same difficult. The control device (8) is for example embodied such that the first thread (2), prepared from a flexible material, exerts a pressure, preferably acting a radial direction, on the several second threads, or that magnetic fields (4) of differing polarities along the first thread (2), prepared from a flexible material and along the second thread (3), may be generated for the selective introduction of an opposing attraction of the threads (2, 3) for reinforcing the guide device (1).
