  We investigate whether the lepton flavor mixing angles in the so-called
democratic type of mass matrix are stable against quantum corrections or not in
the minimal supersymmetric standard model with dimension five operator which
induces neutrino mass matrix. By taking simple breaking patterns of $S_3{}_L
\times S_3{}_R$ or $O(3)_L \times O(3)_R$ flavor symmetries and the scale where
democratic textures are induced as $O(10^{13})$ GeV, we find that the stability
of the lepton flavor mixing angles in the democratic type of mass matrix
against quantum corrections depends on the solar neutrino solutions. The
maximal flavor mixing of the vacuum oscillation solution is spoiled by the
quantum corrections in the experimental allowed region of $\tan \beta$. The
large angle MSW solution is spoiled by the quantum corrections in the region of
$\tan \beta > 10$. The condition of $\tan \beta \leq 10$ is needed in order to
obtain the suitable mass squared difference of the small angle MSW solution.
These strong constraints must be regarded for the model building of the
democratic type of mass matrix
