The invention relates to a measuring device and a method based on a confocal microscopy principle. The inventive device comprises a light source (1), a diaphragm unit (3) for limiting a beam, an imagine optical system (4) for focusing the light (5) which is irradiated by said source on a measurable object (6) and passes through said diaphragm unit. Said device also comprises an optical system (10) for receiving the light (5) reflected from the object and passing through said optical system or another diaphragm unit disposed in an observation beam (7) and an image receiver (10) which is provided with at least two radiation-sensitive sensor elements (13, 14) (pixel). Said invention is characterized in that, in order to obtain the image of an altitude information-containing measurement, the device is also provided with means (11) for modifying the beam optical path length disposed between the light source (1) and/or the image receiver (10), on one side, and the object (6) on the other and the optical distance (d) of a focal point is modifiable in a predetermined manner. In addition, said intention makes it possible to influence the dependence of an accumulation of charges (Q13, Q14) in at least two sensor elements (13, 14) on the light intensity of the observation beam (7) during the exposure time in such a way that a correlation associated with the optical distance (d) of an image plane can be carried out by the imagine optical system (4), thereby making it possible to reconstitute the altitude co-ordinate (zs) of the object by distributing the intensity values obtained during the exposure time from at least two sensor elements (13, 14).