To eliminate an increase of a use amount of material for a permanent magnet so that an increase in motor torque can be attained.

A rotor 14 is constituted by embedding, for instance, four almost rectangular permanent magnets 16 diametrically orthogonal in a rotor core 15 and by providing a starting squirrel cage conductor 17 in the external peripheral part of the rotor core 15. The squirrel cage conductor 17 is arranged by inserting in a squirrel cage conductors slot 17a formed in the rotor core 15, and the end part is connected by an end ring (not shown). A rotor pole pitch angle θk is 90°, when r [mm] in set as the outside diameter dimension of the rotor core 15, h [mm] the depth dimension of the squirrel cage conductor slot 17a, θ [rad] the width angle of the permanent magnet 16, and θk the rotor pole pitch angle, h/r is set to 0.20 to 0.35, and θ/θk is set so as to be in the range of 0.65 to 0.90.