The invention relates to a medical device comprising a generator for generating a magnetic field to be applied to a patient and a supporting structure (2) for the patient. According to the invention, a magnetic field generating head (6) is associated with the supporting structure (2) and can be moved gradually and repeatedly, guided mechanically and/or manually, into a position at a distance from the patient, following a trajectory defined by a bearing guide (5) secured to the supporting structure (2). The trajectory defined by the head (6) extends transversely and/or longitudinally along the length of the surface of the body of the patient to be treated with the magnetic field.