This article shows the present situation, problems and the future vision of urban underground space in Japan. I make it clear what kind of facilities are settled in urban underground space, especially under the road, and how the urban underground space in Japan is classified based on the land ownership and depth. The urban underground space has been recognized as “the Frontier of Urban Development”. But now it became more friendly and popular for our ordinary lives. We have to watch the urban underground space more carefully and understand its characteristics in detail.
