Abstract
After a commencement of "the Act on the Partial Revision of the Act on Promoting Quality Assurance of Public Works", the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) has promoted to introduce various kinds of project delivery, and new contract methods. ECI method is one of new contract methods. It has recently been applied to some building works in Japan. The authors interviewed and analyzed some cases. As the result, it was clarified that there were so many owners who aimed to avoid failure in bidding, there were so many objects applying the technology of contractor, reducing the contraction period, and decreasing design changes. And it was also found that the arrangement of the competitive environment on the time of proposal and owner's leadership at the time of cooperative work were important.
