  A decay of the gravitino dark matter is an attractive candidate to explain
the current excesses of the PAMELA/ATIC cosmic-ray data. However, R-parity
violations are required to be very tiny in low-energy scale. We suggest a
R-parity violation in the right-handed neutrino sector. The violation is
suppressed by a see-saw mechanism. Although a reheating temperature is
constrained from above, the thermal leptogenesis is found to work successfully
with a help of the R-parity violating right-handed neutrino.
