The site is a residential section in the suburb. The distance between houses is expansive and the site is surrounded the rice fields, It is relative rural area. The clients are a husband and wife of four children. They hope a house like a one-room apartment to do parenting naturally and live in friendship. We insertion some factors covers the relation in one space. The space is divided and seen off and on each other, on the other hand, makes a one-room space. Then the activities in the divided spaces can keep independence from the others, and not shutting from the others. Each independent activity influences, and makes wealthy communications. One’s own room in this house has a bare minimum space to put a bed and a closet. To make the rooms small, activities fill out of the room. So making an activity space mutual space for children above the living room in the first floor, and we named that second living room midair living room. The midair living room has a main role of second floor. Using translucent materials as the material of the midair living room. That bears different activities from what is born in the first floor. But the relationship between each living room becomes close. Now, four children are running in the midair living room. The shape of them could be felt, and the house is full of laughter.