The purpose of this study is to select the optimal and minimum transmittance for visual amenity in office buildings. This study progressed as follows. The first, we select 5 films with various transmittance based on the current film makers whose films being used on the windows of office building nowadays and the case study of construction. And then we choose 6 kinds of transmittance as evaluation object including plain glass. The second, we made a mock-up models having different transmittance on the southern windows with model of real scale office building. The third, we select 17 pairs of adjectives for the evaluation of visual comfort on interior or exterior conditions with transmittance factor. The fourth, subjective evaluation experiment was done using selected evaluation adjectives and the result was analyzed. The results are as follows : the minimum transmittance appropriate for the office building is 30%∼40% and the optimal transmittance range is 40%∼60%.