The main problem of Japanese day care centers for the elderly is an institutionalism with collective treatments. The purpose of this paper is to examine the actual conditions of collective treatments there, and to discuss on its factors, structure, and solutions from the point of activities within a place. On-site observations were held in a Japanese day care center and also in Danish senior centers in Aarhus for comparison. Conclusions are as follows; I .In the Japanese day care center, several activity programs are held in a room according to time. Therefore, condition of activities within a place changed as time. 2.Actually, scenes of collective treatments, such as an exercise with all users, were not so much seen. Rather, scenes of mixture of individual activities within a room were most seen. However, it is only a free condition in a 'free program', in a limited time and place. 3.Three conditions of collective treatments were seen: long staying time, stay in a limited room, and uniformity of users' activity patterns. 4. A narrow and limited space is thought to promote collective treatments. That is, classical framework of institution, institutional area = area where services are provided, is thought to be a basic reason of collective treatments. 5.As a solution for collective treatments, it is needed not only to make space divided but also to improve service providing systems and framework of institution.