A permanent magnet type three-phase ac generator includes a stator having 3n (n is an integer) teeth and a tree-phase armature winding and a rotor having 4n magnetic poles each of which has a permanent magnet. The three-phase winding includes 3n coils each of which is wound around one of the teeth and connected to form three phase windings, and each coil wound around a first tooth is connected to another coil wound around another tooth that is fourth from the one of the teeth so that vectors of voltage induced in the connected coils can direct in the same direction.