Abstract: An automatic sliding mechanism for a portable electronic product, particularly a mobile phone handset, is disclosed. The mechanism moves a cover relative to a body of the handset using a piezoelectric actuator which drivingly engages an elongated connecting member fixed on the cover to directly drive the cover. Advantages of weight and volume reduction, permitting miniaturization, and also lower noise are attained, as compared with the use of a conventional sliding mechanism employing DC motor with gear-train-like lead screw, bevel gear and clutch system. Construction is relatively simple and high positioning accuracy is possible with the improved mechanism. A counter-bearing arrangement on the body counter-balances a pushing force from the piezoelectric actuator on the connecting member. Stoppers at the respective ends of the connecting member engage limit switches provided on the body to limit the sliding movement of the cover on the body.