The authors have focused on suitable thermal difference between working in office and taking a rest, and have proposed an airflow control method which can control effective temperature in order to improve workers’ intellectual concentration. In addition, an experiment was conducted to objectively and quantitatively investigate its effectiveness. Airflow can easily control their effective temperature individually. Concretely, a steady airflow is given to improve their arousal while working. A fluctuated slight airflow is given to the workers while talking a rest. Relatively strong airflow is given when they restart their works to encourage their quick switchover. An experiment was conducted where intellectual concentrations were compared under two environments, which were (1)the airflow control environment as a proposed condition and (2)no airflow environment as a control condition. As the result, the average CTR under the proposed airflow condition is significantly higher than that under the control condition. In addition, it was also found that most of the participants felt comfortable, high motivation, and high degree of concentration and didn’t feel sleepy as the result of the questionnaire surveys.