 the depressurizer comprises a suction pump, and a discharge side of the suction pump is connected to a circulating path through which a sucked gas is circulated to a gas introduction path of the pressurizing pump.  0. The quick freezing apparatus according to claim 0, wherein a sterilizer is provided in the gas circulating path of the pressurizer.  0. The quick freezing apparatus according to claim 0, wherein a sterilizer is provided in the gas circulating path of the depressurizer.  0. The quick freezing apparatus according to claim 0, wherein an oxygen absorber is provided in the gas circulating path of the pressurizer.  0. The quick freezing apparatus according to claim 0, wherein an oxygen absorber is provided in the gas circulating path of the depressurizer.  0. The quick freezing apparatus according to claim 0, wherein a gas supply source is provided to the gas circulating path of the pressurizer, the gas supply source selecting and supplying any gas suitable for the object-to-be-frozen such as a nitrogen gas.  00. The quick freezing apparatus according to claim 0, further comprising a gas introducer for, when the door of the freezing store is opened, supplying into the freezing store any gas suitable for the object-to-be-frozen such as a nitrogen gas to increase the inside gas pressure back to the atmospheric pressure level.  00. The quick freezing apparatus according to claim 0, further comprising a gas curtain unit provided near a door opening of the freezing store for producing a layered gas flow from the upper side toward the lower side, the layered gas flow preventing the outside gas from mixing with the inside gas when the door is opened.  00. The quick freezing apparatus according to claim 0, wherein an oxygen absorber is disposed in the freezing store.  00. The quick freezing apparatus according to claim 0, wherein a sterilizer is disposed in the freezing store.  00. The quick freezing apparatus according to claim 0, wherein the pressurizer comprises a pressurizing pump, and a gas introduction path of the pressurizing pump is connected to a circulating path through which a gas inside the freezing store is circulated.  00. The quick freezing apparatus according to claim 0, wherein the depressurizer comprises a suction pump, and a discharge side of the suction pump is connected to a circulating path through which a sucked gas is circulated to the inside of the freezing store.  00. The quick freezing apparatus according to claim 0, wherein an oxygen absorber is provided in the gas 