Turbo fluid machine

A turbo fluid machine includes a housing, a rotating member, and a motor. Part of fluid compressed by a compressor impeller is introduced into a motor accommodation space through an inlet-side flow passage that has an inlet-side fixed throttle, and is discharged from the motor accommodation space through an outlet-side flow passage that has an outlet-side fixed throttle. The outlet-side flow passage includes a connection part connecting to the motor accommodation space. The connection part is formed separately from a clearance between a second partition wall and a shaft, and is located opposite to a connection part of the inlet-side flow passage connecting to the motor accommodation space across the motor in an axial direction of the shaft. The inlet-side fixed throttle and the outlet-side fixed throttle are configured such that pressure in the motor accommodation space is higher than pressure in a turbine-wheel back pressure region.