Abstract: A direction sensitive counting and switching device has an optical system which includes a convex lens and a passive infrared detector composed of sensor elements arranged in at least one double row. The detector is disposed on one side of the convex lens for detecting radiation transmitted along a beam path from persons or objects moving through a detection area of the detector located on the other side of the convex lens and producing output signals in response to the detected radiation. A preamplifier is coupled to the detector for producing amplified output signals from the output signals. An evaluation circuit is coupled to the preamplifier for processing the amplified output signals of the sensor elements and, if the amplified output signals permit a conclusion as to directional movement of a person or object in the detection area of the detector, initiates a counting or a switching process which contains information about direction of movement of the respective person or object in the detection area.