The treatment of X-ray was manipulated with the large focus of X-ray which was produced the capacity of 90 kilovoltage and 30 milliamphere in the distance of 50 centimeter. The germination of each group irradiated with X-ray for 5, 6, and 7 seconds was more delayed in the growth of carrot seed than those of the control group. However the germination of each group irradiated with X-ray for 2,3, and 4 seconds was rather accelerated than those of the control group. The irradiation of ultraviolet light was carried out in the distance of 20 centimeter by Toshiba germidicial lamp which appeared the wavelength of 2537 A˚. The germination of each group irradiated with ultraviolet light for 9, 15, 20, and 40 minutes was more delayed than those of the control group, but the germination of carrot seed was accelerated by adequate dosage of ultraviolet light. Consuquently it was suggested for the author that the inhibited substance contained in carrot seed would be certain fatty substance, because the germination of carrot seed was more accelerated by the treatment of acetone than those of X-ray and ultraviolet light.