A clutch is comprised of a first clutch member including a plurality of first clutch teeth arranged circumferentially around an axis; and a second clutch member including a plurality of second clutch teeth arranged circumferentially around the axis and engageable with the first clutch teeth, each of the second clutch teeth including an end portion internal or external relative to the axis and a pair of side faces facing each other across the end portion, any of the side faces getting in contact with the first clutch teeth when engaged, each of the pair of side faces including a first face being flat and a second face being continuous to the first face and the end portion and having a slope oblique to the first face, wherein one of the first clutch member and the second clutch member is axially movable relative to the other.