  Using lattice QCD with dynamical Wilson fermions, we study I=0 and
$J^{P}=0^{+}$ channel which is constructed by
$\frac{1}{\sqrt{2}}(\bar{u}u+\bar{d}d)|0>$, in order to search for the $\sigma$
meson. Our preliminary result shows that the connected and disconnected
diagrams contribute to the $\sigma$ meson propagator in the same order.
