In a hydraulic servo for a clutch, a cancel plate is disposed on a second
clutch drum that undergoes the same rotation as a second clutch drum
provided with a cylinder portion, in such a fashion that the cancel plate
is restricted from moving to a side opposite from a return spring in an
axial direction. The first clutch drum is disposed, as a separate member,
on the second clutch drum. A step portion of the second clutch drum
prevents the first clutch drum from moving to a side opposite from the
cancel plate. Due to the spring force of the return spring, the oil
pressure in the cancel oil chamber and the oil pressure in the operating
oil chamber, the force that presses the first clutch drum to the step
portion is always greater than the force that presses the first clutch
drum to the cancel plate side.