An interior permanent magnet motor, comprising: a stator; and a rotor rotatably arranged so as to be opposed to the stator, wherein the rotor comprises a rotor core having a plurality of magnet insertion holes formed therein, into which corresponding permanent magnets are respectively inserted, wherein 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, wherein each of the permanent magnets has a radially-inner magnet contour surface, a radially-outer magnet contour surface, and a pair of side-end magnet contour surfaces, wherein each of the magnet insertion holes has a radially-inner insertion hole contour surface, a radially-outer insertion hole contour surface, and a pair of side-end insertion hole contour surfaces, wherein the radially-outer magnet contour surface and the radially-outer insertion hole contour surface are each formed by a first arc surface, wherein the radially-inner magnet contour surface and the radially-inner insertion hole contour surface are each formed by a second arc surface and at least one straight surface configured to suppress movement of the permanent magnet along the magnet insertion hole having the arc shape, and wherein air gap portions are formed between the side-end magnet contour surfaces and the side-end insertion hole contour surfaces under a state in which the permanent magnets are inserted into the corresponding magnet insertion holes, and wherein the side-end magnet contour surface is formed smaller than in the side-end insertion hole contour surface. a stator; and a rotor rotatably arranged so as to be opposed to the stator, wherein the rotor comprises a rotor core having a plurality of magnet insertion holes formed therein, into which corresponding permanent magnets are respectively inserted, wherein 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, wherein each of the permanent magnets has a radially-inner magnet contour surface, a radially-outer magnet contour surface, and a pair of side-end magnet contour surfaces, wherein each of the magnet insertion holes has a radially-inner insertion hole contour surface, a radially-outer insertion hole contour surface, and a pair of side-end insertion hole contour surfaces, wherein the radially-outer magnet contour surface and the radially-outer insertion hole contour surface are each formed by a first arc surface, wherein the radially-inner magnet contour surface and the radially-inner insertion hole contour surface are each formed by a second arc surface and at least one straight surface configured to suppress movement of the permanent magnet along the magnet insertion hole having the arc shape, and wherein air gap portions are formed between the side-end magnet contour surfaces and the side-end insertion hole contour surfaces under a state in which the permanent magnets are inserted into the corresponding magnet insertion holes, and wherein the side-end magnet contour surface is formed smaller than in the side-end insertion hole contour surface.