Abstract: The device is intended for an independent measuring apparatus which can be displaced on a measurement plane on which a part to be measured is immobilized. This device comprises a slide which is displaceable along a slideway of the apparatus perpendicular to the measurement plane, a carriage mounted for displacement in said same direction against opposing forces of two springs intended for the applying of a sensing force, and a support bearing a probe which is mounted for displacement on the carriage in a direction perpendicular to that of the vertical slideway. Upon the search for the point of regression of the probe which is necessary for the detection of the two diametrically opposite points of a bore of the part to be measured, the entire apparatus is immobile on the measurement plane and only the feeler support is displaced on the carriage. Automation of the search for the point of regression is also shown.