PURPOSE: To make it possible with simple constitution to detect the direction of movement of a passing object by making opaque the right half and left half of a circular luminscent body for a photoelectric tube used for counting the number of passsengers of, for example, a bus.

CONSTITUTION: In a light projection and light receiver (both use photoelectric tube), either one of the right half or left half of the lens in front of a light emitting body is made of opaque glass. Then the shape of the output wave of the light receiver is changed according to whether an object 3 to be detected moves in the direction of the arrow mark 4 or the arrow mark 5. Direction of the moving object 3 can be detected by judging the shape of the output wave.