To reduce the power cost and the equipment cost in cleaning the air by removing the water and carbon dioxide in the raw air in an air liquefaction and separation device by an adsorber.

A refrigerant heat exchanger 33 to perform the heat exchange between the pressurized raw air and the low-temperature refrigerant is provided between a raw air compressor 1 and an adsorber 4, a water separator 34 to separate the condensed water in the low-temperature raw air passing from the refrigerant heat exchanger 33 and an air heat exchanger 35 to perform the heat exchange between the dried raw air passing from the water separator 34 and the pressurized raw air before entering the refrigerant heat exchanger 33 are provided.