PURPOSE: To effectually embody a plurality of operation modes by alternately disposing pluralities of heat exchangers and expansion turbines in a cooling stage, and disposing a Joule-Thomson expansion valve on an outlet side of a lowest stage expansion turbine in the cooling stage.

CONSTITUTION: A cryogenic freezing apparatus produces a high pressure gas flow utilizing precooling temperature in a precooling stage I. In a cooling stage II including pluralities of heat exchangers 1-3 and expansion turbines 11, 21, the high pressure gas flow is cooled up to nearly liquefied gas temperature. Further, an article III to be cooled is cooled by a cryogenic refrigerant supplied from the cooling stage III. In this case, the heat exchangers 1-3 and the expansion turbines 11, 21 in the cooling stage II are alternately disposed, through which the high pressure gas fluid supplied from the precooling stage I is alternately successively passed. A Joule-Thomson expansion valve 30 is disposed on an outlet side of the lowest stage expansion turbine 21 in the cooling stage II.