A coil system for the contactless magnetic navigation of a magnetic body in a work space, has a plurality of coils and a current controller for controlling the respective currents in the plurality of coils. In order to navigate the magnetic body to a variably predeterminable position in the work space, the current controller is designed such that the currents in the plurality of coils are such that the magnetic forces generated by the currents and acting upon the magnetic body at multiple positions at the edge of a convex environment around the predetermined position are directed into the environment. The coil system has the advantage that a movement of the magnetic body toward a spatial position is achieved without any mechanical movement of the coil system and without a positioning system for determining the position of the magnetic body. The coil system is utilized particularly in a medical device, wherein a magnetic body in the form of a probe is moved in the body of a patient. In this way, fast navigation of the probe in the patient's body can be achieved without mechanical movements of the patient table or of the coil system.