To provide a communication system for a radio base station for the Internet, by which an interference between radio base stations or an interference between itself and a nearby radar apparatus is hard to generate.

Three different frequencies are allocated to respective radio base stations 41, 42,..., 4n for the Internet, and the radio base stations at three channels (1), (2) and (3) are constituted. The radio base stations at the three channels (1), (2), (3) are face-arranged in such a way that their coverage areas are not adjacent to each other. Antennas for the radio base stations are formed as directional antennas, and the directivity of each antenna is directed to the same direction. Consequently, the radio base stations at the same channel are arranged in a row with the direction of the directivity of each antenna, and the interference of signals between the radio base stations at the same channel can be reduced. When the radar apparatus or the like for weather observation is situated nearby, the directivity of each antenna is set at an angle opposite to the direction of the radar apparatus, and its interference with the radar apparatus can be reduced.