Abstract: A magnetic calender comprises a pair of rotatable parallel rolls (1, 2) and an electromagnet provided with two pole pieces (6, 7) extending parallel to the rolls (1, 2) and joined to a common base (5) through a plurality of magnetic cores (8) having an arrangement which is specularly symmetrical with respect to both the transverse mid-plane and the longitudinal mid-plane of the calender. A coil (9) and a control solenoid (10) located adjacent to the relevant pole piece (6, 7) are wound around each of the cores (8), and the intensity of the current circulating in the coil (9) is controlled by an adjusting unit (11) which is in turn controlled by a control unit (12) which receives and processes the magnetic flux reading carried out by the control solenoid (10).