  We discuss the mass varying neutrino scenario in the supersymmetric theory.
In the case of the model with the single superfield, one needs the soft SUSY
breaking terms or the $\mu$ term. However, fine-tunings of some parameters are
required to be consistent with the cosmological data. In order to avoid the
fine-tuning, we discuss the model with two superfields, which is consistent
with the cosmological data. However, it is found that the left-handed neutrino
mixes with the neutrino of the dark sector maximally. Adding a right- handed
neutrino, which does not couple to the dark sector, we obtain a favorable model
in the phenomenology of the neutrino experiments. In this model, the
deceleration of the cosmological expansion converts to the acceleration near
$z\simeq 0.5$. The speed of sound $c_s$ becomes imaginary if we put
$\omega_0=-0.9$, which corresponds to $m_\nu^0=3.17\eV$. On the other hand, if
we take $\omega_0=-0.998$, which leads to $m_\nu^0=0.05\eV$, $c_s^2$ becomes
positive since $\omega$ evolves rapidly near the present epoch in our model.
