Abstract: A linear stem (3) guides a sliding door (11), which is dragged by a magnetic drive unit between an operating position (W), in which it covers and closes an access mouth (20) to an internal compartment (21) of a sterilizer (1), and an inoperative or opening (N), in which the door (11) moves to a position next to the access mouth (20), thus making it accessible from the outside. The sliding door (11) is operated by movement members (5), comprising a linear module (50), adapted to house a transmission belt (52) stretched between two return wheels (53), one of which is driven by an electric gearmotor (54); a branch of the transmission belt (52) carries a slider (55) with a permanent magnet (56), facing a magnetic plate (6) fixed to the sliding door (11) which is dragged by the magnetic field generated by the cursor (55) in motion.