Natural ventilation has the effect on improving the comfort of the indoor environment. However, this effect has not been clarified since it is difficult to artificially reproduce the same airflow as natural cross ventilation. In this study, the psychological and physiological effects of fluctuating airflow on the human body in hot summer environment were evaluated. The subjective experiments were carried out in a climatic chamber with fluctuating airflow generator, which can generate three airflows with different properties. The following results were obtained. (1)The thermal comfort is obtained by the natural cross ventilation most. Even after the airflow stops, the thermal comfort can be maintained. (2)The allowable environment can be reproduced by using the fluctuating airflow in a hot environment. Especially, the natural cross ventilation is psychological and physiological effective.
