The invention relates to a device for controlling the positioning of two elements (22, 23), for example the blades of a cutting tool, in which one (23) of the elements is stationary while the other (22) is mobile and driven by a geared motor member (21), the position of said mobile element being controlled by the position of a trigger (24). The device comprises: a circuit (3) for controlling the geared motor member； a first stationary Hall effect sensor (40) connected to the circuit (3) and, together with a magnet (41) borne by the mobile element, providing a negative or zero clearance positioning of the two elements； and a second Hall effect sensor (42) connected to the control circuit (3) and, together with a magnet borne by the mobile element, providing the maximum clearance positioning of the two elements. The magnet (41) is positioned such that the north-south axis thereof is perpendicular to the trajectory of same and the first sensor is disposed in an area in which the field vector of the magnet has a component perpendicular to said north-south axis, the sensitive face of the first sensor being parallel to the north-south axis of the magnet.
