A producing method is for an electrical insulating structure to cover an outer surface of a to-be-insulated object. The method comprises: a tape production step of producing a main insulation tape by using a nanoparticle-containing joining macromolecular polymer; a taping step of winding a main insulation tape on outside of the to-be-insulated object to form a main insulated part; a vacuum drawing step, which is performed after the taping step, of vacuum drawing the tape-wound to-be-insulated object; and an impregnation step, which is performed after the vacuum drawing step, of injecting a impregnating macromolecular polymer to impregnate the main insulated part therewith.