A rotor for a rotary electrical machine, the rotor comprising: a rotation shaft; a field core (3, 4) attached to the rotation shaft and configured to integrally rotate with the rotation shaft, the field core (3, 4) comprising claw-shaped magnetic poles; an insulation bobbin secured to the field core (3, 4) 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 (3,4), 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 (3, 4) attached to the rotation shaft and configured to integrally rotate with the rotation shaft, the field core (3, 4) comprising claw-shaped magnetic poles; an insulation bobbin secured to the field core (3, 4) 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 (3,4), 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.