Today, one of the most important problems related to disaster management is how to promote improvement of seismic performance of old housing. This paper presents the change of the number of housing and the density of housing in the 23 special wards of Tokyo from 1978 to 2003 with regards to structure and construction generation. In order to analyze the dataset, the housing is classified into 4 types (wooden housing built before 1980, wooden housing built after 1981, non-wooden housing built before 1980, and non-wooden housing built after 1981). Then, it clarifies how urban vulnerability in Tokyo from the viewpoint of housing seismic performance changed in the three decades after 1978.