  We show that a Chern-Simons term for a gauge field describing a fluctuation
of spins is induced by integrating out hole fields in the presence of
spin-orbit coupling which originates from a buckling of the CuO$_2$ plane.
Through the Chern-Simons term, holes behave like skyrmion excitations in a spin
system and become a superconducting state with $d_{x^2-y^2}$ symmetry after the
antiferromagnetic long-range order is destroyed.
