As more and more tunnels have been constructed to develop new road network, through mountainous ranges or to avoid environmental problems in urban areas, safety in road tunnels has been becoming a major issue. Establishment of tunnel safety measures is the most important task for all those who are engaged in road tunnel design, construction, operation or safety. Based on the past experiences of serious accidents involving fires, efforts to improve safety in road tunnels have been made by establishing technical standards with technological progress and improving emergency facilities in Japan. This paper describes the state of the road tunnel safety technology in Japan.