Introduction:<br> Regional climate is an important element in architectural design. In particular, from the viewpoint of environmental problems and energy conservation, the passive design that uses natural energy effectively by architectural methods is getting its importance. V. Olgyay said there are three steps to create a comfortable indoor climate in a book “Design with climate”. Composite design based on consideration of the outdoor environment, architectural method and equipment is important for passive design. Thus, the importance of the architectural method is explained. Junzo Yoshimura (1908-1997) designed numerous houses in the postwar Japan, emphasizing architectural ingeniousness in addition to machinery facilities, consistently pursued the comfort of the housing. It is assumed that Yoshimura's architecture and thought to the environment are projected in works and discourses such as proportions of space, windows, openings that can be opened to the full, screens and fireplaces. This paper aims to clarify the intentionality towards environmental design in Yoshimura's housing work as seen from the spatial composition of the living room.<br><br> Methods:<br> First, location characteristics of the house were examined. To analyze the location characteristics and the arrangement of the main space, we examined the arrangement of the buildings, the building coverage, and the arrangement of the main spaces.<br> Second, way of closing the main space was examined. The connection between the main space and the outside air, the volume of the main space, and the existence of voids were examined. Furthermore, way of opening the main space was examined. As a characteristic of the window connected to the outdoor, the window-wall ratio and the window openable ratio were examined.<br> Third, based on all these results, spatial composition of closing and opening the main space was classified by the matrix. In addition, fixtures such as the fireplace, shoji screen were examined. From these typologies, Yoshimura's intentionality towards design of combination of thermal and air was analyzed.<br><br> Results:<br> 1) Dominant arrangement of the building and the main space was northward and south in spacious condition such as site area and building coverage.<br> 2) In the whole space, external and internal connecting were almost the same number but the tendency is different for each part. A match between the median of volume and the proportion of the plane favorably used by Yoshimura was found. Windows were mainly based on mechanisms that can be opened and closed. Large and small windows were dominantly used differently with mechanism of ventilation adopted in all directions.<br> 3) Typological analysis of spatial composition showed tendencies when the boundary surface is external, the window-wall ratio was low, and in the case of internal, the window-wall ratio was high. Also, when the room volume was large, the window openable ratio was low, and in the case of small, the window openable ratio was high. Thus, many complimentary combinations were found, indicating that there was an intention to maintain balance in each of the thermal and air systems.<br><br> Conclusion:<br> In this research, on the domestic housing works of Yoshimura, it systematically was examined the spatial characteristics from the viewpoint of architectural design in the thermal environment.