To reduce the burden of a driver and improve the safety of a vehicle operation by optically transmitting various information of a signal lamp modulated concurrently with the luminescence of the signal lamp, amplifying and demodulating the reception signal of an optical transmission receiver installed on the vehicle side, and displaying various information of the signal unit.

The drive signal of a signal lamp 1 constituted of 1G, 1Y, 1R using light emitting diodes as a luminescence source is transmitted from a signal controller 2, and various information such as the color and type of the signal lamp 1 is modulated by a digital signal and optically transmitted into the space. This transmission signal is detected by a receiver 7 on the vehicle 20 side, the signal is amplified by an amplifying circuit 8 and is demodulated by a receiving circuit 9, and various information is extracted from the signal by an information discriminating circuit 13. The content of the extracted information is finally displayed on a display section 10, and a driver can control the travel of a train by confirming this various information.