  A minimal extension of the Standard Model containing the four-color
quark-lepton symmetry is proposed and discussed. The existence of a rather
light extra $Z'$-boson originated from the four-color quark-lepton symmetry is
shown to be compatible with the current electroweak data. The cross sections
$\sigma(e^+ e^- \rightarrow \gamma, Z, Z' \rightarrow \bar f f)$ are
calculated, and their deviations from the SM predictions are shown to be
significant at $\sqrt s \ge 200 GeV$ and available for the measurements at the
LEP200 and future colliders.
