The invention discloses a built-in permanent magnet motor. The motor comprises a stator, a rotor and a plurality of permanent magnets; the rotor is located in the stator; an air gap distance h is leftbetween the rotor and the stator; the rotor comprises a core portion, a plurality of accommodating slots and a plurality of non-magnetic conduction portions, wherein the accommodating slots are equiangularly disposed on the core portion with the center of curvature of the rotor adopted as a center, the non-magnetic conduction portions are disposed in pairs at one end of each of the accommodatingslots which is corresponding to the center of curvature of the rotor, and the non-magnetic conduction portions are symmetrically arranged with the center line of each of the accommodating slots adopted as a center; the plurality of permanent magnets are respectively disposed in the accommodating slots; the core portion includes a plurality of first magnetic conduction portions arranged between twoadjacent non-magnetic conduction portions between two permanent magnets; and each of the first magnetic conduction portions contains a first distance D1, wherein the first distance satisfies a formula I that h<=D1<=4*h. The leakage flux of the built-in permanent magnet motor provided by the invention can be reduced, and the cogging torque of the built-in permanent magnet motor can be reduced.