In a sanding machine for sanding/finishing panels made of wood, metal or the like, an abrasive belt is moved so as to cause it to come into contact with a panel by a plurality of thrust elements, which are distributed inside the abrasive belt, and are moved perpendicularly to the panel by respective actuator cylinders, each of which has an output rod which is moveable between a lowered operating position and a raised rest position under the thrust of a pressurised gas supplied in a continuous manner to an upper chamber of the actuator cylinder and in a selective manner to a lower chamber of the actuator cylinder itself.