This study is intended to clarify the usefulness of an open type plan in a public housing design. We define an open type plan as a house design in which many rooms are connected by fittings such as sliding doors, fusuma, etd., used for partitioning off. 3 ppublic housing units were investigated and their occupants behavior was compared. Comparisons were made on the following items; (1) how each room in the house is used (2) the movement of fittings and arrangement of furniture (3) evaluation by residents As the result, we came to the conclusion that the life styles of residents in open type houses were diversified and the rooms were used in accordance with their own life style.