A motor comprising: a stator comprising a plurality of teeth arranged to be spaced apart in a circumferential direction of the stator; and a rotor (20, 30) comprising a plurality of magnets (24, 34) arranged inside or outside the stator and configured to rotate while electromagnetically interacting with the stator, the plurality of magnets (24, 34) including a switch magnet having a switchable magnetic polarity, wherein the plurality of teeth comprises first teeth and second teeth, wherein each of the first teeth and the second teeth comprises: a teeth body portion (611a, 611b) extending in a diameter direction of the stator; an outer step portion (612a, 612b) extending from an outer end of the teeth body portion (611a, 611b) toward both sides in the circumferential direction of the stator; and an inner step portion (613a, 613b) extending from an inner end of the teeth body portion (611a, 611b) toward both sides in the circumferential direction of the stator, wherein a cross section of the teeth body portion of the second teeth is smaller than a cross section of the teeth body portion of the first teeth, wherein a magnetic polarity of the switch magnet is switched by the first teeth, wherein the rotor (20, 30) comprises an outer rotor disposed outside the stator and an inner rotor disposed inside the stator, wherein the outer rotor and the inner rotor are configured to rotate independently of each other, and wherein one of the outer rotor and the inner rotor comprises the switch magnet. a stator comprising a plurality of teeth arranged to be spaced apart in a circumferential direction of the stator; and a rotor (20, 30) comprising a plurality of magnets (24, 34) arranged inside or outside the stator and configured to rotate while electromagnetically interacting with the stator, the plurality of magnets (24, 34) including a switch magnet having a switchable magnetic polarity, wherein the plurality of teeth comprises first teeth and second teeth, wherein each of the first teeth and the second teeth comprises: a teeth body portion (611a, 611b) extending in a diameter direction of the stator; an outer step portion (612a, 612b) extending from an outer end of the teeth body portion (611a, 611b) toward both sides in the circumferential direction of the stator; and an inner step portion (613a, 613b) extending from an inner end of the teeth body portion (611a, 611b) toward both sides in the circumferential direction of the stator, a teeth body portion (611a, 611b) extending in a diameter direction of the stator; an outer step portion (612a, 612b) extending from an outer end of the teeth body portion (611a, 611b) toward both sides in the circumferential direction of the stator; and an inner step portion (613a, 613b) extending from an inner end of the teeth body portion (611a, 611b) toward both sides in the circumferential direction of the stator, wherein a cross section of the teeth body portion of the second teeth is smaller than a cross section of the teeth body portion of the first teeth, wherein a magnetic polarity of the switch magnet is switched by the first teeth, wherein the rotor (20, 30) comprises an outer rotor disposed outside the stator and an inner rotor disposed inside the stator, wherein the outer rotor and the inner rotor are configured to rotate independently of each other, and wherein one of the outer rotor and the inner rotor comprises the switch magnet.