PURPOSE: To bring refrigerant gas in a vapor-liquid mixed state near a theoretically equilibrium state of mixed refrigerant, separate a gas component which is rich in a low boiling point component from a liquid component which is rich in a high boiling point component and enable this separator to be installed to a corner of an inner wall of an outer box of a refrigerator.

CONSTITUTION: An air separator 9 is provided with a triangular prism-shaped vessel main body 10 where there is installed a honeycomb material 11 which is bored along the direction of gas flow in the upper half of the vessel, an inlet pipe 12 installed to the upper par of the vessel main body, a gas out-flow outlet pipe 13 installed to the upper part of the vessel main body opposed to the inlet pipe and a liquid outflow outlet pipe 14 installed to the lower part of the vessel main body. The separator 9 is placed into contact with a corner of an inner wall of an outer box of a refrigerator 15 and fixed thereto. Therefore, this construction makes it possible to separate a gas component which is rich in a low boiling point component from a liquid component which is rich in a high boiling point component and install the separator to the corner of the inner wall of the refrigerator with ease.