This paper describes the developmental effort of the closed-loop cryoablation device. The device is designed to have spacious cooling region to be treated at incompetent great saphenous vein (GSV). The cryoablation device, contains three separate J-T (Joule-Thomson) expansion parts, so that it can have 20 cm long cooling area for target ablation. The cooling probe is operated in a closed system by a commercial compressor with R22. The discharge and the suction pressures of the compressor are approximately 13 bar and 3 bar, respectively. The lowest temperature is measured around 257 K, and the temperature nonuniformity over the long device was ± 1.7 K.