The invention relates to an air cycle refrigeration and cooling system, and turbine unit for the air cycle refrigeration and cooling. The air cycle refrigeration and cooling system for sequentially performing compression by a precompression means (2), cooling by a heat exchanger (3), compression by a compressor (6) of a turbine unit (5), cooling by other heat exchangers (8, 9), and adiabatic expansion by an expansion turbine (7) of the turbine unit (5). The turbine unit (5) has a compressor wheel (6a) and a turbine wheel (7a) that are installed on a common main shaft (13) and drives the compressor wheel (6a) by power generated at the turbine wheel (7a). The main shaft (13) is rotatably supported by rolling bearings (15, 16), and thrust force applied to the main shaft (13) is received by an elerctromagnet (17). A pressure uniformizing means (81) for uniformizing gas pressure at both ends of the rolling bearings (15, 16) is provided.