The invention solves the prior art problem of signals not being transmitted between ground and vehicle when a train stops so that a cross point of a loop coil or a boundary between two loop coils is positioned between antennas disposed on a front side and a rear side in a direction of travel of the train. The present invention provides an arrangement in which two or more antennas are disposed on a front side and a rear side in the direction of travel of the train and providing a difference in signal levels received via the respective antennas, so that even when the train stops with the cross point of the loop coil positioned between antennas disposed on the front side and the rear side in the direction of travel of the train and the signals received via the front-side antenna becomes reverse phase with the signals received via the rear-side antenna and the signals are cancelled out, the signals having a higher reception level remains without being cancelled out, and therefore, a given level of transmission and reception can be obtained.