  We show that the neutrino masses with large mixing between \nu_\mu and
\nu_\tau are naturally reproduced in a supersymmetric E_6 grand unification
model with an anomalous U(1)_X symmetry. We propose a simple scenario which
incorporates a novel mechanism called `E-twisting' by which all the
characteristic features of the fermion mass matrices, not only the
quark/lepton's Dirac masses but also the neutrino's Majorana masses, can be
well reproduced despite all the members in 27 of each generation are assigned a
common U(1)_X charge.
