A support mechanism is adapted to support an upper body of an electronic element, and the upper body can be turned pivotally relative to a lower body of the electronic device. The support mechanism includes a base, a plate, a transmission shaft and a torsional force generating device, in which the base is fixed on the lower body and the plate is fixed on the upper body. Furthermore, the transmission shaft is passed through and installed on the base and the torsional force generating device is wound around the transmission shaft. One end of the torsional force generating device is extended outward and fixed on the plate so as to couple the base to the plate and process a pivotal turn.