The purpose of this study is to make a model of housing demand estimation, and to simulate the number of affordable rental houses need to supply from 1991 to 2000. In this paper, the framework of the model, the objective living standard and the result of estimation by the model is shown, and we make a discuss about the effect of housing policy of local prefecture's government. Yamaguchi prefecture is selected as an example for the study. If the population become 1,500,000 in 2000, objective households of affordable rental housing are estimated about 52,600. Considering the supply in the market and original housing standard, the number of rental houses need to supply by government is 2,280.