||"In these several years, Japanese public clients have begun to examine the effectiveness of applying the ISO9000s quality management system to building construction projects. One of the major interests of the public clients applying ISO9000s is to mitigate their own burden generated by the supervision of the works. It is, however, quite a sensitive issue whether the supervision can be mitigated successfully without jeopardising the level of quality of the buildings, because the supervision is one of the most important jobs for securing the quality demanded by the clients.This paper introduces our newly developed computer aided decision making supporting system which optimises the trade-off relation between the mitigation of the supervision and the assurance of the quality. The system is called Revised Quality Function Development (R-QFD), which we modified and revised QFD method. In terms of building construction industry, QFD can be one of the powerful methods for incorporating the information about needs and desires of clients, A/E, constructors and users.R-QFD was applied to a newly built post office whose client is Ministry of Posts and Telecommunications(MPT). The needs and the desires of 27 supervisors in MPT and 8 site engineers in joint venture contractors were investigated according to R-QFD tables. The tables are expressed as a QFD drawing which consists of a list of 10 project properties, a list of 18 quality items, a list of MPT supervisory jobs divided into 90 tasks, a list of planning assurance which is a new concept introduced in this paper, and a list of 59 ISO9000s requirements.As a result, the difference of the needs and the desires between MPT and contractors was clarified numerically. The supervisory tasks which can be omitted and the tasks which should not be omitted was classified numerically. Through these numerical evaluations, the scope of supervision for MPT and the terms of reference for contractors were defined efficiently. As the project is still under construction, the effectiveness of R-QFD will be examined after the inspection of completed works."