A torque sensor is less likely to lower detection accuracy. A screwing machine includes a motor including a stator and a rotor rotatable about a rotation axis, a gear case, a planetary gear, an internal gear connected to the planetary gear, a torque sensor including a front plate coupled to the internal gear, a rear plate supported by the gear case, a hollow portion located between the front plate and the rear plate, and a strain gauge fixed to the hollow portion, a bearing located between the stator and the rear plate and supporting at least a part of the rotor, and a bearing box surrounding the bearing and supporting the bearing.