To structure a moving body communication base station by irreducible facility addition by using a transmission line that a road information system device uses as a moving body communication base station dedicated line in common.

The transmission line 12 is protected by a corrosionproof steel pipe 11, etc., and signals from a on-road beacon transmission line 13 and a wired dedicated line 14 for a moving body communication base station are transmitted thorugh it. The corrosionproof steel pipe 11 is fitted to a post with a metallic belt, etc. Then the wired dedicated line 14 for the moving body communication base station and on-road beacon transmission line 13 are connected to a moving body communication base station part 24 and an on-road beacon part 23 respectively. In this case, various cables such as a power line, a twisted pair line, a coaxial cable, and an optical fiber cable are usable for the transmission line 112,. Thus, the transmission line of a road information system device which is already laid is utilized to structure the moving body communication base station by the irreducible facility addition.