A computer aided facility management systems are now used extensively in many areas such as maintenance of electric power equipment. However most of these systems possess data management structures that deal with only 2 dimensional space. The 3D graphic system that enables users to explore the 3D space interactively and examine 3D spatial views of the environments would be very useful for facility management. In this paper, we describe about a facility managememt system based on computer generated 3D virtual city environment. This prototype system supplies the user interactive operations even if the virtual city is very large. Moreover, this system can deal with not only 3D spatial information but also temporal information. Using this system, the user can get the facility management environment that is very useful for management, analysis and planning etc.