  Stimulated by the idea of PRISM, a very high intensity muon ring with rather
low energy, we consider possibilities of observing CP-violation effects in
neutrino oscillation experiments. Destructive sum of matter effect and
CP-violation effect can be avoided with use of initial $\nu_{\rm e}$ beam. We
finally show that the experiment with (a few) $\times$ 100 MeV of neutrino
energy and (a few) $\times$ 100 km of baseline length, which is considered in
this paper, is particularly suitable for a search of CP violation in view of
3-generation nature of CP violation.
