The energy consumption of commercial and business sector has rapidly increased and saving energy in office building has been encouraged. However, it may not only affect comfort of office workers but also give negative effect on their intellectual productivity. It is therefore necessary to design office room environment from the viewpoint of both energy saving and productivity of office workers. In this study, we focus on airflow among the thermal environmental factors. The airflow control method which improves intellectual productivity has been proposed and its effectiveness was evaluated objectively and quantitatively by conducting several evaluation experiments. As the result, the average concentration time ratios (CTRs) under the proposed airflow condition were 61.1% while that under no airflow condition was 54.6%. The proposed airflow control showed 6.5% point significant improvement of CTRs (p＜0.001).