The present invention relates to a freeze-dryer, for compressing a high-temperature high-pressure compressor (10 ), a condenser 20 for condensing the refrigerant of the high temperature and high pressure, of the plurality of the gas-liquid separator (31, 32), and the gas-liquid separator 31 to the gas-liquid separating the condensed refrigerant into gas refrigerant and liquid refrigerant mixture the liquid refrigerant is expanded and the gas refrigerant injection supply of the low-temperature low-pressure state through a plurality of heat exchangers 41 and 42 and the heat exchanger 42 to be supplied to the next step after the heat exchange with the liquid refrigerant condensed by expanding the first condensed refrigerant to obtain cooling air of different temperature, the second cooling unit (51,52), a refrigerant such that the refrigerant for cooling the plurality of the rough part 51 and 52 returned to the compressor 10 and recovery flow path 60, the first auxiliary cooling cycle for cooling the refrigerant in advance of the transfer state before the gas-liquid separator 31, 70 and the auxiliary heat exchanger (80) is provided in the condenser (20). Thus, by the provision of an auxiliary cooling cycle and advance the auxiliary heat exchanger for cooling the refrigerant in the state before being transferred to the gas-liquid separator in a condenser, and to maintain proper operation of the zoom operation environment given to relieve the pressure, and, the first gas-liquid by providing the overload prevention means between the separator and the second heat exchanger, the second heat exchanger to obtain a good cooling effect, such as to prevent overloading at the initial operation or rapid cooling during the second heat exchanger.본 발명은 동결건조기에 관한 것으로서, 고온고압으로 압축시키는 압축기(10)와, 상기 고온고압의 냉매를 응축시키는 응축기(20)와, 상기 응축된 혼합냉매를 기상냉매와 액상냉매로 기액 분리시키는 복수의 기액분리기(31,32)와, 상기 기액분리기(31)의 액상냉매가 팽창 분사되어 저온저압 상태로 공급되고 상기 기상냉매는 상기 액상냉매와 열교환되어 응축된 후 다음 단계로 공급되도록 하는 복수의 열교환기(41,42)와, 상기 열교환기(
