A three-phase permanent magnet-type synchronous motor configured to significantly reduce cogging torque. The motor includes a rotator and stator each having either permanents magnets or teeth. The number of magnetic poles of the rotator or stator is P and a number of slots of the stator or rotator is N, and a fraction of 2N/3P has a value greater than zero and less than one. The tooth width of the teeth of the stator or rotator in a circumferential direction is ½ of the slot pitch of the stator or rotator.