PURPOSE: To extend an effective communication range by connecting in series plural light emitting and photodetecting ports located scatteredly by a branching means in an infrared ray communication system to perform communication with a moving body.

CONSTITUTION: The transmission data from a center computer 1 is modulated by a transmission/receiving controller 2, irradiated from light emitting elements in the light emitting and photodetecting ports 31∼3n via the branching means 51∼ 5n, received by photodetectors of the light emitting and photodetecting ports provided in a moving body 4 like a personal computer, moving robbot or the like, demodulated further by the transmission/receiving controller to give a prescribed motion to the moving body. The light emitting and photodetecting ports are placed at nearly 10m intervals by using a scattered infrared ray to extend the moving range of the moving body to the range of location of the light emitting and photodetecting ports. The polling control system utilizing time division is used for plural moving bodies.