Abstract: A device for driving the revolving tripod of a two-way turnstile includes a wheel (1) keyed onto a shaft (2) together with a trilobate cam (3) and the tripod, a positioning mechanism engaging said cam (3) and suitable to cause the rotation thereof upto one of three stop positions 120.degree. apart, and two specular mechanisms for locking said wheel (1) each one including an L-shaped lever (9, 9') rotating around a pin (13, 13') and driven by a rod (10, 10') in turn driven by an electromagnet (11, 11') which overcomes the bias of a spring (12, 12'). The wheel (1) is shaped as an equilateral triangle with convex sides having a particular peripheral profile including a series of teeth and steps with straight flanks and different heights (14, 15a, 15b, 15c, 16), the spring (12, 12') being possibly arranged on the rod (10, 10') so as to keep the lever (9, 9') in contact with or away from the wheel (1) when the electromagnet (11, 11') is not activated.