The number of tunnels in Japan is huge, since 60% of the land is covered by mountains. The maintenance of tunnels has become an increasingly important issue in Japan, where most of the tunnels have been used for more than 40 years. Maintenance helps a tunnel keep in healthy condition so as to have a long service life, which is beneficial for the public budget comparing to a new construction project. When and how to conduct maintenance to the tunnels synthetically taking into account the cost and the performance of tunnels require extensive studies. In this study, a road tunnel database is constructed by means of GIS utilizing the collected data for maintenance management of tunnels in Nagasaki prefecture, Japan. The approach of asset management is introduced into the database for accurately predicting the future conditions of tunnels and searching for the optimal maintenance management method. Using this system, evaluations of the tunnel performances and the maintenance cost for tunnels to reach the required performance level are conducted, which could be a helpful base for the future maintenance management.