We have been examining how an intelligent lighting system affects energy consumption in the office. In this paper, we evaluate the traditional intelligent lighting system at the office and how to improve the best use of the intelligent lighting system by each user. The user in the large office is not able to change the level of luminance. Moreover, the traditional lighting system is not able to specify which desk is occupied or not occupied by each worker. The proper use of lighting control affects the power consumption, and the worker sometimes forgets to change the occupancy status after leaving the office, which affects the energy. This paper argues to find the best model of the intelligent lighting system to save energy by using the technology of sensing devices for detecting the occupancy of the desk. As a result, we found that each worker has the individual lighting system, and the energy of the office is reduced by improving the intelligent lighting system.