Recently, renovation of the bathrooms are often conducted, since it is known that the impression of the bathroom may affect the impression of the whole facility. Cleanliness may be the most important factor, yet most bathrooms in Japan meets the requirements. Pleasantness and other impressions maybe the next factors to be considered. In that case, not only the bathroom booth, but lighting environment surrounding mirrors will be important. Previous studies on lighting environment of mirrors considers the suitable lighting patterns, color temperature and its brightness. Since brightness evaluation depends on the brightness of the target as well as the ratio of the surrounding brightness, surrounding environment has to be considered as well. Therefore, this research aims to find out first the present circumstances of the lighting environment around mirrors in public and commercial facilities. In addition, experiment using adjustment method was conducted to find the suitable brightness surrounding mirror.<br> In order to grasp the present situation, lighting survey and evaluation was done in public and commercial facilities. 9 train station bathrooms varying in used years were selected as public facilities. 2 commercial buildings varying in age were selected, and in total 20 different interior bathrooms were evaluated. Items of the survey were lighting methods being used, number of mirrors, and its distance till the back wall. In addition to lighting environment survey, 16 subjects were asked to evaluate 6 items of 7 rating semantic differential method evaluation. Corresponding with evaluation, illuminance values and luminance distribution were measured. As a result, brightness had correlation with the vertical illuminance, yet pleasantness did not. The lighting methods were mostly using down light and adding indirect light surrounding mirror, yet distance till the back wall varied from 1.2 meters to almost 8 meters, creating various lighting environment. Based on the hypothesis that background brightness influencing the evaluation, controlled experiment was conducted.<br> In a white experimental room, general lighting that brightens the back wall and mirror lighting that brightens the face were set. Lighting the general light in 4 different patterns (0, 100, 300, 900 cd/m²) and 2 different mirror (full-length and half-length) were created as experimental settings. 20 subjects were asked to adjust the power of the mirror lighting until the suitable brightness (lower, optimal, and upper). As a result, facial luminance and luminance ratio were not constant, and it varied by the background luminance. Generally, brighter the background brightness, brighter the facial brightness as well. Optimal range using various lighting indexes were derived using logistic regression analysis. In addition, the mirror light of the pattern without general lighting was adjusted brighter than the pattern with general lighting lit a little. This showed that there may be an optimal background lighting that has dimmest facial luminance. As a result of the analysis, facial luminance and the background luminance could be expressed as a plane using the power of 2 lighting equipment used. Using linear algebra, powers of 2 lighting equipment that forms dimmest facial luminance were derived. Then background luminance and luminance ratio at that point was calculated. Both full- length and half- length patterns had dimmest around background luminance of little over 200 cd/m² and facial luminance of around 60cd/m².<br> For further study, more factors that effects the pleasantness of the mirror usage has to be considered.