It is important to reduce construction duration in private sales and lease business for management of cash now in the owner's aspect. However, because the concept of standard duration hasn't been established in the domestic construction industry, it is difficult to present the standard of duration estimate. To solve this problem, this paper (1) grasped the effecting elements considered in the duration estimate through referring the existing literature related to the schedule management, (2) accomplished a comprehensive research on actual duration based on office buildings through the questionnaire survey and the expert interview, (3) presented the collected research data analyzed by effecting elements as standard duration, (4) compared standard duration with actual duration of countries advanced in construction projects as well as analyzed them, and then (5) raised the necessity of duration reduction in the domestic construction industry