The invention concerns a handling device comprising, in combination, a mechanical equilibrium mechanism (10) with low reaction time, having an arm (20) whereof the proximal end (22) is locked on a pivot pin (18) and whereof the distal (26) is adapted to support a load (10), a force sensor (30) positioned in a selected site for detecting apparent weight variation the load (10) resulting from a force being exerted on said load in response to an operator's movement, servo feed-back means (32) actuated by the force sensor (30), and an actuator (34) controlled by the servo feed-back means (32) and connected to the arm to assist the operator's movement. The invention is applicable in particular to robot arms or the like.