Abstract: A process of and apparatus for liquefying a dry gas with low boiling point in a first circuit through heat exchange with a main refrigerating fluid in a second circuit itself pre-cooled to its at least partial liquefaction through heat exchange with an auxiliary refrigerating fluid in a third circuit, wherein, for a same amount of treated products, the required total compression input power for the refrigerating fluids is reduced by performing in said third circuit an intermediate condensation between the two last compression stages followed by a phase separation, the gaseous phase being compressed to a high pressure in the last compression stage whereas the liquid phase is compressed to a high pressure by a pump and recycled to a cryogenic heat exchanger for cooling the gas initially in the moist state thereby at least partially drying same.