The purpose of this paper is to trace a process of housing supply of the residential complex that planned by the housing co-op and to point out that the form of the dwelling units and the ownership played an important role in defining the direction in which the housing estate was transforming. Kobushi-danchi, the object of this study, was composed of 490 semi-detached houses (980 households), which were built in the suburbs of Tokyo in 1966. It is assumed that the residents took part in the housing supply, because Kobushi-danchi was planned by the housing co-op and improved by the resident organization after the development. Therefore this paper, based on the research using documents, focuses on the planning, the ownership and the residents' activities to analyze the change in this project.