In order to make clear the causes of sterility of rice flowers damaged from wind, we investgated on the pollination, pollen-germination and fertilization of the flowers exposed to the artificial strong wind generated by the wind tunnel. (1) Many sterile flowers were found after the treatment, especially among flowers bloomed on the day of the treatment. (2) The number of pollination and germination of flowers bloomed on the day of the treatment varies widely, but, on the other hand, we recognized little difference between those of untreated flowers and flowers bloomed after the day of the treatment. (3) It was found that flowers, bloomed just before or just after the beginning of the wind treatment, were unpollinated of if not, pollinated only a little, and it is considered that the fact was one of the causes of the occurrence of sterile flowers. Among flowers bloomed in the late half stage of the treatment, on the contrary, there were many pollinated extremely, and, although these show the low percentage of germination, it is considered not to be the direct cause of the sterility, because they have many germinated pollens. (4) As the causes of being unpollinated or polinated only a little, it is considered that blooming of flwors was hastened by the wind, nevertheless the dehiscence of anthers did not follow close to the blooming of flowers. We may suppose such a mechanism to be plausible from the model experiment by the artificial stimulus such as rubbing with fingers.