  Lepton flavor violating processes are obtained from the mixing between
ordinary leptons and vectorlike SU(2)_L doublet leptons which may originate in
E_6. The effects of this lepton mixing are, however, suppressed naturally by
the hierarchy of the charged lepton masses. In the supersymmetric model,
significant effects of lepton flavor violation may appear rather through
slepton mixing, which is in the present case generated by radiative corrections
with ordinary-exotic lepton couplings. We are especially interested in the mu
-> e gamma decay. In the model without the bare mass term of vectorlike
leptons, the supersymmetric contributions are rather suppressed due to the
approximate U(1)_e X U(1)_mu. It is, however, remarkable that they are
substantially enhanced by tan^6 beta. Then, B(mu -> e gamma) might be
comparable to the experimental bound for large tan beta. In the model with the
bare mass term, much larger contributions are obtained through slepton mixing.
These investigations show that the supersymmetric effects on lepton flavor
violation due to the vectorlike leptons can be observed in the near future
experiments.
