The purpose of this study is to develop a mathematical model in order to analyze relationship between demand distribution and locational planning of ambulatory welfare institutions for elderly people. A model is developed as an institution choice model and takes two important factors such as the maximum commuting distance and using times per a week of day service center. Using the model several simulations are done for the case of Kanazawa City and study the results. As a result, it is revealed that some important patterns can be analyzed such as service coverage area by institutions and the number of selectable institutions for elderly people according to the planning conditions. The model also can be used for analysis of suitable institutional location pattern although the model has to be improved.