A device for the photoelectric measuring of an opaque or transparent object to be measured includes a photoelectric sensor (4) and a measuring optics (3) which directs measuring light originating from a measurement field of the object to be measured (6) onto the sensor (4). A control electronic (5) cooperates with the sensor (4) for the processing of the electrical signals produced by the sensor. The sensor (4) includes at least two individually controlled and concentrically arranged partial sensors (41, 42, 43), and the control electronics (5) includes switching means (51) by which the partial sensors (41, 42, 43) can be selectively switched on or off-line. The use of a photoelectric sensor made of or divided into several partial sensors enables a purely electronic and therefore simple and fast selection of different effective measurement field sizes.