A vessel tracking device for use with a pressure source has an elongate introduction element configured for introduction into a vessel of a human body, the introduction element having a proximal end and a distal end, and the distal end having a flexible distal end portion containing an internal cavity that is closed at the distal end. A pressure adjuster is configured for communication with said pressure source. The introduction element has a connection channel connected to the pressure adjuster at the proximal end of the introduction element, the connection channel being connected with the internal cavity and placing the internal cavity in communication with the pressure source, with the pressure adjuster controlling an internal pressure in the internal cavity. The distal end portion has different wall portions that are differently deformed as the internal pressure is adjusted, to produce a change in direction of the distal end controlled by the pressure controller.