The purpose of this study is to suggest a defect-repair management and judgement of apartment housing for the private housing construction company. The objectives are : 1) to investigate how the defect-repair were managed and 2) to suggest the range, period of defect-repair and the proper managial size of housing company. Data were collected by the interviews from the heads of management departments of housing construction companies. Twenty-one companies selected were divided into three groups according to the amount of housing supply. Major result were as follows : 1) departments of defect-repair in housing construction company are divided into sub-system according to the size of housing supply. 2) the judgement of the range and period of defect-repair are extracted. They are, according to the order of their importance, constructional defect, functional defect, aesthetical defect and the defect in use.