  We study the effects of neutrino oscillation on supernova neutrino in the
case of the inverted mass hierarchy ($m_{3} \ll m_{1} < m_{2}$) as well as the
normal mass hierarchy ($m_{1} < m_{2} \ll m_{3}$). Numerical analysis using a
realistic supernova and presupernova model allows us to discuss quantitatively
a possibility to probe neutrino oscillation parameters. We show that
information about the mass hierarchy can be obtained if $\theta_{13}$ is rather
large ($\sin^{2}{2 \theta_{13}} > 10^{-3}$) and that $\theta_{13}$ can be well
probed by SuperKamiokande if the neutrino mass hierarchy is the inverted case.
Errors due to the uncertainty of the original neutrino spectra and the Earth
effect are also discussed.
