A rotor, the rotor being defined by laminated electromagnetic steel plates, the electromagnetic steel plates each comprising a plurality of through hole groups running through the electromagnetic steel plates, and each of the through hole groups comprising a plurality of through holes, wherein the rotor is divided into four magnetic pole regions (M1, M2, M3, M4), each including one of the through hole groups, wherein each magnetic pole region (M1, M2, M3, M4) includes a first d axis, a second d axis located on a side of the first d axis in a rotation direction of the rotor, and one q axis located between the first and second d axes and being 45 degrees from the second d axis, wherein the first and second d axes are central axes of respective magnetic poles of the rotor, each magnetic pole region (M1, M2, M3, M4) includes: a first magnet being located substantially at a center of one of the through holes in a circumferential direction, and a second magnet being accommodated in one of the through holes between the second d axis and the q axis of a magnetic pole region (M1, M2, M3, M4), characterized in that in each magnetic pole region (M1, M2, M3, M4), an entire outer peripheral surface of the rotor between the second d axis and the q axis is recessed radially inward relative to an entire outer peripheral surface of the rotor between the first d axis and the q axis, so that the rotor is noncircular when observed in an axial direction. the rotor is divided into four magnetic pole regions (M1, M2, M3, M4), each including one of the through hole groups, wherein each magnetic pole region (M1, M2, M3, M4) includes a first d axis, a second d axis located on a side of the first d axis in a rotation direction of the rotor, and one q axis located between the first and second d axes and being 45 degrees from the second d axis, wherein the first and second d axes are central axes of respective magnetic poles of the rotor, each magnetic pole region (M1, M2, M3, M4) includes: a first magnet being located substantially at a center of one of the through holes in a circumferential direction, and a second magnet being accommodated in one of the through holes between the second d axis and the q axis of a magnetic pole region (M1, M2, M3, M4), characterized in that in each magnetic pole region (M1, M2, M3, M4), an entire outer peripheral surface of the rotor between the second d axis and the q axis is recessed radially inward relative to an entire outer peripheral surface of the rotor between the first d axis and the q axis, so that the rotor is noncircular when observed in an axial direction. a first magnet being located substantially at a center of one of the through holes in a circumferential direction, and a second magnet being accommodated in one of the through holes between the second d axis and the q axis of a magnetic pole region (M1, M2, M3, M4), characterized in that in each magnetic pole region (M1, M2, M3, M4), an entire outer peripheral surface of the rotor between the second d axis and the q axis is recessed radially inward relative to an entire outer peripheral surface of the rotor between the first d axis and the q axis, so that the rotor is noncircular when observed in an axial direction.