  We examine the mechanism of gaugino condensation in supersymmetric theories
within a Nambu-Jona-Lasinio type approach. We investigate the effective
Lagrangian description of higher energy theories that include some moduli
fields in the gauge coupling constant. First we consider supersymmetric QCD
with and without a mass term. We can find a phase transition in massless
theory, but when we add a mass term, such a phase transition disappears. We
also examine a model with a dilaton dependent coupling constant and find that
it is very similar to supersymmetric QCD. Application of our method to
supergravity is also examined.
