The purpose of this study was to clarify the space use pattern and the daily living activities of the elderly with dementia in the common space (dining room, day corner) of nursing home in Japan. The subjects were six units of the 2 nursing homes in Tokyo. For this, researcher visited from September 5 to December 5 and collected data by observations of behavior of the elderly with dementia in common space and interviews with staff for the information about basic characteristics of the elderly with dementia and administration and operation of the facilities. The data were analyzed using the frequency and percentage with SPSS 11 program and recorded in the form of behavior map. The results revealed as follows: first, 6 types (self-concentration type, physical environment-interest type, passive others-interest type, staffs-interaction type, other elderly-interaction type, visitors-interaction type) of the daily living activities of the elderly with dementia in common space were founded. Second, the daily living activities of the elderly with dementia in common space tended to focus on self-concentration type and physical environment-interest type. Third, physical environmental characteristics of common space affected space usage pattern of the elderly with dementia. And it was perceived like as living oriented space, social interaction space, facility space, staff oriented space. Conclusively it was suggested to plan dining space as semi-private space, day comer as semi-public space.