[en] The process of hydrogen liquefaction due to the heat exchange with vaporizing helium is analysed. The temperature conditions of heat exchangers are considered taking into account the thermodynamical properties of gases and the gas flows are calculated. To liquefy cooled hydrogen at gas pressure equal to 1 atm, twice as much helium is needed in comparison with the cooling from room temperature to condensation temperature. To increase the liquefaction efficiency half as much again the cooling to 15 deg K of hydrogen compressed to 25 atm is proposed followed by its orificing to atmospheric pressure. The results of calculation are tabulated