To carry out signal light aspect control and a rolling stock presence detection by means of a simple strwcture and to carry out information transmission and direction control by sending a modulated signal wave to a transmitter unit by means a modulation unit on the basis of an information signal sent from an information output unit and transmitting the information outputted from the modulation unit to each track circuit by means of a transmitter unit.

A modulation unit 18 modulates a carrier wave with a frequency f2 generated in a carrier wave generation unit 17 with an information signal, which shoes the up directional advance aspect and is provided with a frequency fGU, so as to send it to a transmitter unit 19. The modulated wave, which carries an information signal with a frequency fGU and is provided with a frequency f2, is transmitted by means of the transmitter unit 19 to track circuit 1T, 2T via a matching transformer 7. The modulated wave with a frequency f2 transmitted to the track circuit 2T is received by a receiving unit 11 of a track circuit device 6b arranged in the boundary between the track circuit 2T and the track circuit 3T. By means of a similar process, a modulated wave, which is provided by modulating a carrier wave with a frequency f3 by the information signal showing the up direction advance aspect and possessing a frequency fGU, is transmitted from the transmitter unit 19 of the track circuit device 6 to the track circuits 2T, 3T.