The invention provides a rotor for a dynamo-electric machine which is capable of reducing deformation of magnetic poles due to centrifugal force or noise generated by vibrations without deteriorating characteristics of the dynamo-electric machine. The rotor includes a plurality of deformation preventing members. Each of the deformation preventing members is attache on each magnetic. Each of the deformation preventing members has elongated portion pressed to aginst to the side wall of the magnetic poles. A first deformation preventing members attached on the first magnetic poles and a second deformation preventing members attached on the second magnetic poles also are used. The first and second deformation preventing menber are holded to one another.