Abstract
Since the Preservation Districts for Groups of Historic Buildings system was enacted in 1975, many areas which have been preserved historical townscape have been involved in many kinds of works on preservation of the landscape, placing the focus on the daytime view, however the night landscape also get increasingly attention by policy of night tourist spot or streetlight maintenance in recent years. Then, I had surveyed the true state of night landscape formation in the illumination event and every day and aimed at analyzing the effects and the points at issue being brought to the area by the project.