An optoelectronic protective device for providing switching signals when an unauthorized object is present in a passageway or an opening through a wall. A light source illuminates the opening, and a camera forms a picture of at least one of the wall surfaces defining the opening. A camera forms a picture of at least one of the wall surfaces and directs it onto a position resolving light receiver that generates picture signals for evaluation to determine if an unauthorized project is in the opening. The light source, the light receiver, the camera, as well as a control unit, are mounted in a housing that is configured to be secured to at least one of the wall surfaces of the opening so that it extends only negligibly into the opening, and the light source illuminates a spatial angle and the camera has an angular field of view that are sufficiently large so that objects having a predetermined minimum size present in the opening are reliably detected.