  The Nambu - Bogoliubov - de Gennes method is applied to the problem of
superconducting QCD. The effective quark-quark interaction is described within
the framework of the Nambu - Jona-Lasinio model. The details of the phase
diagram are given as a function of the strength of the quark-quark coupling
constant $G^{\prime}$. It is find that there is no superconducting phase
transition when one uses the relation between the coupling constants
$G^{\prime}$ and $G$ of the Nambu - Jona-Lasinio model which follows from the
Fierz transformation. However, for other values of $G^{\prime}$ one can find a
rich phase structure containing both the chiral and the superconducting phase
transitions.
