An interior permanent magnet motor includes a stator and a rotor rotatably arranged so as to be opposed to the stator. The rotor includes a rotor core having a plurality of magnet insertion holes formed therein, into which corresponding permanent magnets are respectively inserted. The plurality of permanent magnets and the plurality of magnet insertion holes are each formed into an arc shape that is convex toward a center side of the rotor. When a shortest distance between the adjacent magnet insertion holes is defined as an inter-pole shortest distance (L), a ratio of the inter-pole shortest distance (L) to an outer diameter (D) of the rotor is 0.035≦L/D≦0.045.