A rotor for a rotary electrical machine, the rotor comprising: a rotation shaft ; a field core attached to the rotation shaft and configured to integrally rotate with the rotation shaft, the field core comprising claw-shaped magnetic poles ; an insulation bobbin secured to the field core and comprising: a winding portion ; wherein the insulation bobbin comprises flanges on both sides of the winding portion in an axial direction of the winding portion ; and wherein the rotor further comprises: a field coil wound in a space region defined by the winding portion of the insulation bobbin and the flanges of the winding portion , wherein a winding-start receiving groove in which a winding-start lead wire of the field coil is received is formed in an inner surface of one of the flanges , and a holder is disposed on that flange and located on a radially outer side of the winding-start receiving groove , and wherein the holder is at a position corresponding to a valley between the magnetic poles of the field core , characterized in that , the holder is formed with a holder groove continuous to the winding-start receiving groove , and extending at an angle relative to a radial direction of the insulation bobbin , the winding-start lead wire of the field coil is received in the winding-start receiving groove and the holder groove and held by the holder groove , and wherein the winding-start receiving groove is a concave open groove extending in the tangential direction at the intersection between the flange and the bottom surface of winding portion , and wherein the holder groove is located on an extension line of the winding-start receiving groove . a rotation shaft ; a field core attached to the rotation shaft and configured to integrally rotate with the rotation shaft, the field core comprising claw-shaped magnetic poles ; an insulation bobbin secured to the field core and comprising: a winding portion ; wherein the insulation bobbin comprises flanges on both sides of the winding portion in an axial direction of the winding portion ; and wherein the rotor further comprises: a winding portion ; wherein the insulation bobbin comprises flanges on both sides of the winding portion in an axial direction of the winding portion ; and wherein the rotor further comprises: a field coil wound in a space region defined by the winding portion of the insulation bobbin and the flanges of the winding portion , wherein a winding-start receiving groove in which a winding-start lead wire of the field coil is received is formed in an inner surface of one of the flanges , and a holder is disposed on that flange and located on a radially outer side of the winding-start receiving groove , and wherein the holder is at a position corresponding to a valley between the magnetic poles of the field core , characterized in that , the holder is formed with a holder groove continuous to the winding-start receiving groove , and extending at an angle relative to a radial direction of the insulation bobbin , the winding-start lead wire of the field coil is received in the winding-start receiving groove and the holder groove and held by the holder groove , and wherein the winding-start receiving groove is a concave open groove extending in the tangential direction at the intersection between the flange and the bottom surface of winding portion , and wherein the holder groove is located on an extension line of the winding-start receiving groove . <EOS>