Workplaces for office workers can be considered ‘second places’, after their ‘first places’. On working days, they not only work at their workplaces but also refresh or do personal matters around their workplaces. Therefore, various places are constructed by office workers around their workplaces as their ‘third places’. In this study, the office workers’ behavior to use efficiently the places is defined as ‘place-constructing’ from the viewpoint of Environmental Behavior Study (EBS), and place-constructing around workplaces was focused down and considered. We clarify changes of office workers’ place-constructing in office-moving as one case of environmental transition. One department of the company that moved its office from Kanda to Shinagawa in 1999 was selected as one of the settings of the study. Kanda is a mixed-used downtown area in Tokyo, and Shinagawa is a newly redeveloped area, also in Tokyo. The office in Kanda was in an eight-storied building and the floor size was 200 square meters. New office in Shinagawa is in a 31-storied building and floor size was 3000 square meters that is one part of large-scale urban project called ‘Shinagawa Inter City’. Thus these workplaces had different characteristics from each other.The methods were interviews and questionnaires of workers of the departments who worked at both workplaces. In the interviews, 7 workers were drafted, and the difference of each workplaces and the life around workplace were discussed. As a result, many topics about places for frequently visiting, dropping in, refreshing at, feeling ‘mine’, and walking around workplace, were mainly discussed. So these places and walking behavior were regarded as significant and having close relations to office workers’ behavior to use efficiently places around workplace. From this result, the questionnaires were organized and sent to 15 workers. The questions were about locations, reasons, activity about places for frequently visiting, and locations for dropping in, refreshing at, feeling ‘mine’, and routes for commuting and strolling.The ways of ‘place-constructing’ in each area were quite different. Architectural types of constructed third places in Kanda were restaurants, bookstores, coffee shops, general stores, banks. On the other hand in Shinagawa, were only restaurants. In Kanda, many third places were constructed around workplaces. But in Shinagawa, the number of third places was small and the architectural types of the places were limited. Third places in Shinagawa were mostly inside of ‘Shinagawa Inter City’, and they are dependent on workplace and treated as an extension of workplace. But essential third places are independent of both home and workplace, and these places constructed in ‘Shinagawa Inter City’ should be called ‘semi-third places’.Because various advanced functions for office workers in workplace in Shinagawa, for example dining hall, library, lounge, were furnished, many places for refreshing at, feeling ‘mine’ were constructed in workplace, and office workers took various activity into these places. In Kanda, there weren’t any other functions in workplace, and there were many third places around workplaces, so office workers often took their work out to third places.At next stage, KJ-Methodology were used, architectural types and activities about places for frequently visit were considered, 7 patterns of place-constructing were found. Before everything, places for friendship with fellow workers were constructed around workplace, and then places for doing personal matters, friendship with girlfriend, boyfriend or family, and taking lunch were constructed. These patterns show the progressive order and activeness of place-constructing around workplace. In Kanda there were many active patterns, but in Shinagawa there were many inactive patterns. A pattern that no place constructed around workplace increased from 1 to 3 in this environmental transition.Besides, same methodology used, locations for dropping in, refreshing at, feeling ‘mine’, and the extent and the shape of routes for commuting and strolling were considered, 5 patterns of walking around workplace were found. In Kanda, there were many patterns that office workers were well walking, dropping, and refreshing. However, in Shinagawa there were many patterns that office workers were not so much walking, dropping at places far from workplace, and refreshing at semi-third places. Three routes for commuting and many routes for strolling were constructed in Kanda, but only one route for commuting and few routes for strolling were constructed in Shinagawa. Complementary relationships were found between third places and strolling routes, and between semi-third places and commuting routes, respectively.Towards the improvement of quality of office workers’ life around workplace, the above EBS knowledge should be adopted in case of planning or designing city environment, including offices. For example, even if it is small area, a mixed-used landscape or not planned and left area could be significant third places for office workers in case of urban development.ReferenceRay Oldenburg: The Great Good Place, Marlowe & Company New York, 1999