PURPOSE: To provide a follow-up position controlling system which uses visible laser for control wherein a multitype photo-detecting module using multiple infrared photo-detecting elements for on/off output is generated, and a direction detection sensor which detects direction on the side of infrared signal transmission is provided and some objects to be controlled, provided in multiple numbers, are selected for tracking.

CONSTITUTION: In a multitype photo-detecting module 2, multiple photo-detecting elements 1... are attached to photo-detecting bodies 3, with built-in signal processing circuits, so as to adjoin each other at specified interval. In each of photo-detecting element, the photo-detecting body 3 having a photo-detecting element is provided with a photo-detecting guide 4 far making the photo- detecting field of view narrower. The photo-detecting body 3 is provided with an amplifier for amplifying output from the photo-detecting element, and an output circuit for shaping the output wave form from the amplifier and outputting on/off signal. The multiple photo-detecting elements 1... are arranged on the photo-detecting bodies 3 at the angle of regular intervals each other.