Various research studies about the life span of buildings have been carried out, since the life span of buildings is one of the basic concerns for land use forecast. In this paper, we propose a mathematical model that can stably estimate the value of probability that buildings will be demolished or will remain within the specific time interval. As an application of the model, we propose and examine a method that can estimate the average age of buildings within a district, using time series digital maps taken from densely built-up areas of Tokyo.
