A capper head for general purpose usable even when the specifications of a cap including screw pitches are changed without using a fixed gear and a lifting cam determining a lifting stroke and the timing thereof. The rotational output of a servo motor is transmitted to a screw mechanism through a sliding engagement part, and a screw shaft is lowered while rotating for capping. The lowering stroke of the screw shaft is allowed by the sliding engagement part. In capping, even if the strokes of a rotating chuck ) and an output shaft are different from the lowering stroke by the screw mechanism , a stroke difference absorbing part absorbs the stroke difference therebetween since a spring in combination with a spline transmitting the rotation is deflected in the axial direction.