A sensor for scanning a surface with an oscillating cantilever (12), made from piezoelectric material that is suitable for a transverse oscillation of the free end of a beam, holding an electrically conductive probe tip (14) on the free end of the beam in transverse direction, a first deflection electrode (26A, 26B) and an inversely phased second electrode (28A, 28B, 28C) being provided to collect charges that are separated within the space of the deflection electrodes (34, 36). The cantilever (12) is provided with at least one electrode (30) in addition to the deflection electrodes (26A, 26B, 28A, 28B, 28C) that provides electrical contact to the tip (14), the at least one additional electrode being located in a region on the deflecting beam where the surface charge density due to the strain caused by beam deflection (34, 36) is smaller than in the region where the deflection electrodes are located.