To provide a tunnel illumination control device which can prevent the control functions from not functioning caused by abnormalities, failure, etc., in an apparatus or a transmission path.

A tunnel illumination control device for a car road is equipped with illuminations 2 and 3 in a plurality of groups installed in tunnels 1A and 1B, light receiving parts 8 and 9 installed for respective groups of illuminations, control boards 4 and 6 for processing the signals given from the light receiving parts 8 and 9, site apparatus 5 and 7 to control the illuminations in the tunnels 1A and 1B in conformity to the signals given from the control boards 4 and 6, and a plurality of transmission paths 10, 12A and 12B for transmission signals between the control boards 4 and 6.