Abstract: An apparatus for contactlessly measuring a measurement object is proposed, which has an optical sensor, the optical sensor having an optical probe having a light source and a measurement objective for directing a light beam onto a measurement object and a receiver device for detecting a light beam reflected from the measurement object and generating a corresponding measurement signal; an advancing apparatus for altering the distance between the optical sensor and the measurement object in a first coordinate direction in a manner dependent on the measurement signal generated by the receiver device; and an evaluation unit for determining the coordinates of the measurement point on the measurement object.