The invention relates to a device for maintaining in position one end of an element driven in rotation by a fluid circulating in a tube (12), the other end of said element being free, said device being of the type which comprises a part forming a bearing (1) and adapted to be rigidly attached to one end of the tube, and an element (4), mounted for rotation relative to the part forming a bearing (1) and adapted to be attached to one end of the movable element (13). In accordance with the invention, the part forming a bearing (1) is a one-piece part made of a rigid material that is capable of being elastically deformed, said one-piece part comprising at least two flanges (2) spaced apart by such a distance that they can be force-fitted into an open end of said tube (12) to bear elastically on its inner wall so as to rigidly join the part forming a bearing (1) to the tube.