This house is planned for a family, husband, wife and their son. This small house has 8 levels of floor between entrance in the basement to the roof terrace in order to constitute every space not in concentrated way by big void but reciprocal relation of each space. This arrangement makes the notion of floor ambiguous and the continuity of space compatible with the hierarchy of space. In order to realize this spatial constitution with small gap we adopt steel structure. We use visible steel frame in 40mmx125mm flat bar that allow us to make each space flow without gravity.