  The chiral phase transition at finite temperature is studied by using the
Schwinger-Dyson equation in the dual Ginzburg-Landau theory, in which the dual
Higgs mechanism plays an essential role on both the color confinement and the
spontaneous chiral-symmetry breaking. At zero temperature, the quark condensate
is strongly correlated with the string tension, which is generated by
QCD-monopole condensation, as $\langle {\bar q}q \rangle^{1/3}
\stackrel{\propto}{\scriptstyle \sim} \sqrt{\sigma}$. In order to solve the
finite-temperature Schwinger-Dyson equation numerically, we provide a new
ansatz for the quark self-energy in the imaginary-time formalism. The recovery
of the chiral symmetry is found at high temperature; $T_{_{C}}\sim 100{\rm
MeV}$ with realistic parameters. We find also a strong correlation between the
critical temperature $T_{_{C}}$ of the chiral symmetry restoration and the
strength of the string tension.
