  We consider possibilities of observing T-violation effects in neutrino
oscillation experiments with very long baseline (~ 10000 km) using low energy
neutrino (~ several hundreds MeV). We show that the matter effect effectively
changes only the first-second generation mixing angle, respecting solar
neutrino deficits and atmospheric neutrino anomalies. The effective mixing of
the first-second generation in the Earth grows up to maximum by resonance. This
effect enables one to search T violation in case the first-second mixing angle
is small. We discuss its implications to the observations of T-violation
effects in long baseline experiments.
