This paper reports on the life time of various kind of Japanese houses estimated by using a method similar to making life table of human being. Defining the representative value of life time as when the half of a cohort should be demolished, wooden residential houses have 38-year life, and wooden apartment houses have 32-year life. Another four type of houses, those of reinforced concrete and those of steel frame, were also investigated. And their life times do not differ much from those of the wooden ones. Two types of office buildings were also investigated for reference, and they had similar or a little shorter life time than the houses.
