  Using the CCFR data for the Gross--Llewellyn Smith (GLS) sum rule, we extract
the strong coupling constant via Borel resummation of the perturbative QCD
calculation. The method incorporates the correct nature of the first infrared
renormalon singularity, and employs a conformal mapping to improve the
convergence of the QCD perturbation expansion. The important twist-four
contribution is calculated from resummation of the perturbation theory, which
is based on the ansatz that the higher--twist contribution has a cut
singularity only along the positive real axis on the complex coupling plane.
Thus obtained, the strong coupling constant corresponding to the central GLS
experimental value is in good agreement with the world average.
