  Based on the (approximate) chiral symmetry of QCD Lagrangian and the bound
state assumption of effective meson fields, a nonlinearly realized effective
chiral Lagrangian for meson fields is obtained from integrating out the quark
fields by using the new finite regularization method. As the new method
preserves the symmetry principles of the original theory and meanwhile keeps
the finite quadratic term given by a physically meaningful characteristic
energy scale $M_c$, it then leads to a dynamically spontaneous symmetry
breaking in the effective chiral field theory. The gap equations are obtained
as the conditions of minimal effective potential in the effective theory. The
instanton effects are included via the induced interactions discovered by 't
Hooft and found to play an important role in obtaining the physical solutions
for the gap equations. The lightest nonet scalar mesons($\sigma$, $f_0$, $a_0$
and $\kappa$) appearing as the chiral partners of the nonet pseudoscalar mesons
are found to be composite Higgs bosons with masses below the chiral symmetry
breaking scale $\Lambda_{\chi} \sim 1.2$ GeV. In particular, the mass of the
singlet scalar (or the $\sigma$) is found to be $m_{\sigma} \simeq 677$ MeV.
