To provide a motor-integrated magnetic bearing apparatus that improves workability in assembly and that is made compact.

A rotor 28a of a motor 28 is arranged in a main axis 13 supported by rolling bearings 15 and 16 and a magnetic bearing, and a stator 28b in a housing 14. A motor coil cooling passage 31 having an inflow port 31c and an outflow port 31d of cooling liquid, which is open to a stator fixing surface of the housing 14, is arranged inside the stator 28b. An input-side cooling passage 32 communicated to the motor coil cooling passage 31 at the inflow port 31c and an output-side cooling passage 33 communicated to the motor coil cooling passage 31 at the outflow port 31d are disposed in the housing 14. An input port 36 making cooling liquid flow into the input-side cooling passage 32 from outside and an output port 37 making cooling liquid flow out from the output-side cooling passage 33 are disposed on a surface toward an axial direction of the housing 14.