Ethylene production was measured in mungbean hypocotyls in the presence of far infrared rays emitted from ceramic power using a gas chromatography. Both IAA- and 1-aminocyclopropane-1-carboxylic acid (ACC)-induced ethylene production was inhibited by 20-30% of the control by indirect application of the ceramic powder. These data suggested that far infrared rays emitted from ceramic powder might act on the conversion step of ACC to ethylene. Furthermore, the activity of ACC oxidase, acting on the conversion of ACC to ethylene, was also inhibited by 20% of the control by indirect treatment of the ceramic powder. These results suggested the possibility that inhibition of ethylene production by far infrared rays emitted from ceramic powder could be used for increasing the periodof storage and freshness of crops, fruits, and vegetables.