To accurately decide a switching point for radio systems with acquired distance information.

A transmission section 13 and a transmission frame 22 arranged at a front part and a rear part of Shinkansen trains are connected, and train rolling measuring instruments 15 and 23 are connected to the transmission section 13 and transmission frame 22; and a control section 12 is connected to one of the transmission section 13 and transmission frame 22, and distance information measured by, for example, the train rolling measuring instrument 23 positioned at the rear part in the traveling direction of the Shinkansen trains is transmitted to the control section 12. The control section adds a correction value for transmission delay between the train rolling measuring instrument 23 having taken the measurement and the control section 12 to the transmitted distance information to decide a switching point where the radio systems of a radio section are switched.