We study an energy-scale dependence of the lepton-flavor-mixing matrix in the minimal supersymmetric standard model with the effective dimension-five operators which give the masses of neutrinos. We analyze the renormalization group equations of kapp
a_{ij}s which are coefficients of these effective operators under the approximation to neglect the corrections of O(kappa^2). As a consequence, we find that all phases in $kappa$ do not depend on the energy-scale, and that only n_g-1 (n_g: generation number) real independent parameters in the lepton-flavor-mixing matrix depend on the energy-scale.
The Superkamiokande experiment suggests the large flavor mixing between nu_mu and nu_tau. We show that the mixing angle receives significant corrections from the renormalization group equation (RGE) when both the second and the third generation neutr
ino masses are larger than O(0.1eV). This means that the mixing angle must be small at the decoupling scale of right-handed neutrinos in the model containing a sterile neutrino nu_s with the mass spectrum of m_nu_s = m_nu_e << m_nu_mu = m_nu_tau.
