This invention provides a highly efficient and highly reliable automotive rotating electrical machine which can reduce heat generation of a rare earth magnet and can reduce an eddy-current loss within an iron core. A rare earth magnet material is compression molded into a compression molded product. The compression molded product of the magnet material is impregnated with a precursor of SiO<SUB>2</SUB> to provide a magnet formed of the rare earth magnet material bound with an amorphous form of film-like SiO<SUB>2</SUB>. The use of this magnet can increase electrical resistance within the magnet and can reduce the generation of heat. Further, the formation of an iron core by compression molding of an iron powder of particles having a surface covered with an electrical insulating film can reduce the generation of heat within the iron core and can realize an improved reliability of the rotating electrical machine. Further, the generation of heat within the magnet is reduced, and an eddy-current loss within the iron core is reduced, resulting in an improved efficiency of the rotating electrical machine.
