  The Gutzwiller wave function for the three-band Hubbard model on a two
dimensional CuO$_2$ plane is studied by using the variational Monte Carlo (VMC)
method in the limit $U_d \to \infty$, where $U_d$ is the Coulomb repulsion
between holes on a Cu site. The VMC results for the energy and the fraction of
$d$-holes are compared with those of the Rice-Ueda type Gutzwiller
approximation (GA). The difference between the VMC and the GA results are most
pronounced at half-filling, and away from half-filling the two results agree
well in both the hole-doped and the electron-doped cases. The doping dependence
of the momentum distribution function is also studied.
