Disclosed are a method and compound to insufficient pollen formation due to high-temperature and low-temperature stress, and restore pollen fertility. Also disclosed are a fertility restorative agent, which contains auxin as an active ingredient, and a method to restore fertility in gramineous plants that includes spraying auxins. Further disclosed are a fertility restorative agent, which contains a substance that hinders the effects of auxin as an active ingredient, and a method to restore rice fertility that includes spraying the substance that hinders the effects of auxin. It is preferable to use 10