A stator of an electric motor (40) has windings (44) and a stator core (43) in which eighteen teeth (71), around which the windings (44) are wound, are formed circumferentially. A rotor of the electric motor (40) has magnets (72) and a rotor core (46) in which six insertion holes (73), into which the magnets (72) are inserted, are formed circumferentially. The magnets (72) are rare-earth magnets of a grain boundary diffusion type having a residual magnetic flux density Br of from 1.36 to 1.42 T. The total area of magnet-parallel cross-sections (84) of the teeth (71) is from 0.56 times to 0.93 times the total area of tooth-facing surfaces (83) of the magnets (72).