  SUSY effects on various flavor changing neutral current processes are
discussed in the minimal supergravity model and the SU(5) grand unified theory
with right-handed neutrino supermultiplets. In particular, in the latter case
the neutrino Yukawa coupling constants can be a source of the flavor mixing in
the right-handed-down-type-squark sector. It is shown that due to this mixing
the time-dependent CP asymmetry of radiative B decay can be as large as 30% and
the ratio of $B_s$-$\bar{B}_s$ mixing and $B_d$-$\bar{B}_d$ mixing deviates
from the prediction in the standard model and the minimal supergravity model
without the neutrino interaction.
