This paper aims to clarify relationship between behavior of elderly residents and spatial structure of nursing homes, focusing on the quality and meaning of common spaces, especially semi-private and semi-public zone. For this objective, 3 types of nursing home with private rooms were surveyed by means of mapping of activities of the residents/care staffs, behavior observation and deep interviews. The findings are as follows : 1)Each zones of each facilities were used differently. Some places were used in only activity programs, but some places were used frequently by the residents independently, in which diverse activities and behaviors were observed. 2)Use pattern of common spaces or extent of living area in facilities of the residents were influenced by both degree of independence of them and care environments of the facilities (including building environment and care philosophy). 3)Meaning of semi-private and semi-public zones were quite different from each 3 facilities in their characteristics of publicness, then the common spaces could be considered not as mono-hierarchical zones but as various public sphere.
