With the purpose of eradicating melon flies, Dacus cucurbitae COQUILLETT, an aerial distribution system was devised for the effective use of the sterile insect technique. Sterile pupae were placed in an emergence box which was stored in an air-conditioned container. The emerged files were reared with sugar and water, being followed by an anesthetization with a chilling treatment (3℃) in the second or third day after emergence. The immobilized flies were placed in an apparatus which was specifically designed for broadcasting sterile files effectively. The apparatus was installed one each on both sides of the helicopter. The files were released in an orderly manner with a device of a spiral type adapter. Inside temperature of the apparatus was maintained low to the possible extent of a coolant: i.e. 3℃ at the start, followed by a gradual rise, reaching 5℃ in 30 min and 10℃ in 180 min after the helicopter took off. The survival rate in the emergence box was approximately 81% in 3 days after emergence. The survival rate and the flying capability after chilling were 73.3 and 68.1%, respectively. The survival rate of flies before and after passing through the release apparatus was 98.9 and 98.3% and the flying capability was 93.6 and 91.3%, respectively. There results indicate that the original high quality of the flies was not seriously damaged during the test period.