A transmission/reception device (101) on a mobile body (10) uses a plurality of antennas (100). It is assumed that the antennas (100) are arranged so as to be decentralized in the advance direction of the mobile body and the distance between the antennas at both ends is so large that it cannot be ignored as compared to the radio base station interval. Since the radio wave from the base station 102-1 is strong in 100-1 and the radio wave from the base station 102-2 is strong in 100-2 as compared to the center, it is possible to expect more stable communication as compared when the antennas arecentralized. Thus, it is possible to increase the interval between the base stations and reduce the hand over speed and frequency as well as realize a higher band use efficiency than in the conventional technique.