A clutch to be combined with a differential device rotating about an axis, comprising: a gear including a first face perpendicular to the axis, and plural first clutch teeth being arranged in a circumferential direction around the axis; and a clutch member movable in the axial direction relative to the gear, the clutch member including a second bottom, and plural second clutch teeth being arranged in a circumferential direction around the axis and respectively projecting from the second bottom to be capable of respectively meshing with the plural first clutch teeth, characterized in that: the gear includes a first bottom receding in an axial direction from the first face; the plural first clutch teeth respectively project from both the first face and the first bottom; the clutch member includes an internal peripheral wall connecting internal ends of the plural second clutch teeth and projecting in the axial direction toward the gear; and each of the plural first clutch teeth comprises a first tooth top face opposed to the second bottom, each of the plural second clutch teeth comprises a second tooth top face opposed to the first bottom, the internal peripheral wall is so dimensioned as to come in contact with the first face when the second clutch teeth engage with the first clutch teeth, whereby the internal peripheral wall prevents the first tooth top faces from coming in contact with the second bottom and prevents the second tooth top faces from coming in contact with the first bottom. a gear including a first face perpendicular to the axis, and plural first clutch teeth being arranged in a circumferential direction around the axis; and a clutch member movable in the axial direction relative to the gear, the clutch member including a second bottom, and plural second clutch teeth being arranged in a circumferential direction around the axis and respectively projecting from the second bottom to be capable of respectively meshing with the plural first clutch teeth, characterized in that: the gear includes a first bottom receding in an axial direction from the first face; the plural first clutch teeth respectively project from both the first face and the first bottom; the clutch member includes an internal peripheral wall connecting internal ends of the plural second clutch teeth and projecting in the axial direction toward the gear; and each of the plural first clutch teeth comprises a first tooth top face opposed to the second bottom, each of the plural second clutch teeth comprises a second tooth top face opposed to the first bottom, the internal peripheral wall is so dimensioned as to come in contact with the first face when the second clutch teeth engage with the first clutch teeth, whereby the internal peripheral wall prevents the first tooth top faces from coming in contact with the second bottom and prevents the second tooth top faces from coming in contact with the first bottom. the gear includes a first bottom receding in an axial direction from the first face; the plural first clutch teeth respectively project from both the first face and the first bottom; the clutch member includes an internal peripheral wall connecting internal ends of the plural second clutch teeth and projecting in the axial direction toward the gear; and each of the plural first clutch teeth comprises a first tooth top face opposed to the second bottom, each of the plural second clutch teeth comprises a second tooth top face opposed to the first bottom, the internal peripheral wall is so dimensioned as to come in contact with the first face when the second clutch teeth engage with the first clutch teeth, whereby the internal peripheral wall prevents the first tooth top faces from coming in contact with the second bottom and prevents the second tooth top faces from coming in contact with the first bottom.