To solve the problems of sunshine lack and provide sufficient sunlight in an interior space, it might be necessary to apply some active sunlighting systems to building. Among these systems, mirror sunlighting device, which is simple, cheap and easily constructed, is very useful to apply for small buildings and houses. This study aims to analysis the initial performance evaluation of the device developed for this study. The system consists of a 90cm in diameter with clear top dome, a base, two reflective mirrors, a sun tracking controller, and an activator. The clear top dome was placed on the roof of four-story building and the second reflective mirror was placed on front of ground level of the north facing room. The experiments were conducted under clear sky from 11:00 a.m. to 3:00 p.m. Illuminance on the floor was measured by using Topcon IM-5. Luminance were measured by ProMetric 1400 on the window, wall and floor. Some findings on the efficiency of the device and the improvement of the luminous environment are discussed.