  We investigate the contribution from each Dirac modes to the Polyakov loop
based on a gauge-invariant analytical relation connecting the Polyakov loop and
the Dirac modes on a temporally odd-number lattice, where the temporal lattice
size is odd, with the normal (nontwisted) periodic boundary condition. The
dumping factor in the relation plays crucial role for the negligible
contribution of low-lying Dirac modes to the Polyakov loop. The zero-value of
the Polyakov loop in the confinement phase is due to the ``positive/negative
symmetry'' of the Dirac-mode contribution to the Polyakov loop. In the
deconfinement phase, there is no such symmetry.
