To provide a turbo refrigerating machine capable of maintaining the refrigerating gas pressure and lubricating oil of a plurality of compressors at proper values and realizing a stable operation.

An oil recovery device 9 for recovering lubricating oil mixed in a refrigerant to oil tanks 3 and 14 is provided in a refrigerant system. A recovery system of the oil recovered by the oil recovery system 9 is connected to venturi tubes 21, 22, 31 and 32 arranged in a lubricating oil system so that the recovered oil is returned to the oil tanks 3 and 14. When compressors 1 and 12 are switched to the operation of a single compressor or to the simultaneous operation of a plurality of compressors, the balance piping of a refrigerant gas side is connected to that of a liquid side by a balance piping having venturi tubes. Opening/closing valves 29 and 30 are provided in the balance piping to open/close the valves under the peration.