An alternating current generator for a vehicle, in which durability is improved, magnetic fluxes are prevented from leaking, and noises are reduced. In the alternating current generator, a ring made of a steel material is disposed so as to abut against field core claws and on the outer peripheral side of a field winding. Resin permanent magnets which are molded onto the ring are disposed between the field core claws so as to abut against the field core claws, respectively.