Abstract: An apparatus for counting the number of passing persons by stature, wherein a projector for radiating light toward the head of a passing person, a light receiving lens for receiving light reflected from the person's head, and a light position detector are arranged as one set at an upper portion of a gateway or a passageway. The light receiving lens converges reflected light to different light-received positions of the light position detector according to the height of the reflective position. The light position detector outputs electric signals which differ according to the reflected light received at the light-received positions and a counting operation is performed discriminatively for every output of the signals.