Abstract: An optical data reader having an improved servo system for maintaining an orthogonal relation between the optical axis of an irradiating light beam and the surface of a recording disc onto which the light beam is directed. The data reader includes a holding mechanism for the optical system, movable in the radial direction of the disc, and a tilt servomechanism. The tilt servomechanism includes flexible members for supporting an objective lens of the optical system of the reader so as to be rotatable and movable in a plane including the rotational axis of the disc, a detector for detecting deviation from the orthogonal, and a drive device for moving the objective lens in accordance with the detection signal.