The method and device according to the invention provide for recovery of high-pressure oxygen and high-pressure nitrogen by low-temperature separation of air in a distillation-column system. This system comprises a high-pressure column, a low-pressure column, and a main condenser. A first air feed stream is cooled at a first subcritical pressure in a main heat exchanger to approximately dew point and introduced at least partially into the high-pressure column. A second air feed stream is brought to a second, supercritical, pressure, cooled, depressurized, and introduced at least partially into the distillation-column system. A first partial stream of the second air feed stream is cooled in the main heat exchanger, and a second partial stream is cooled in a high-pressure heat-exchanger system. The first and second partial streams are then merged and work-expanded in a liquid turbine.