  We show that the large mixing between $\nu_\mu$ and $\nu_\tau$ observed by
the SuperKamiokande collaboration is a quite natural prediction in a large
class of seesaw models. This large mixing is basically due to the unparallel
family structure suggested from the observed mass hierarchies in quark and
lepton mass matrices. We show that the unparallel family structure is
automatically realized in ``coset-space family unification'' model based on
$E_7/SU(5) \times U(1)^3$. This model also suggests the small angle MSW
solution to the solar neutrino problem.
