  The phase structure associated with the chiral symmetry is thoroughly
investigated in de Sitter spacetime in the supersymmetric Nambu-Jona-Lasinio
model with supersymmetry breaking terms. The argument is given in the three and
four space-time dimensions in the leading order of the 1/N expansion and it is
shown that the phase characteristics of the chiral symmetry is determined by
the curvature of de Sitter spacetime. It is found that the symmetry breaking
takes place as the first order as well as second order phase transition
depending on the choice of the coupling constant and the parameter associated
with the supersymmetry breaking term. The critical curves expressing the phase
boundary are obtained. We also discuss the model in the context of the chaotic
inflation scenario where topological defects (cosmic strings) develop during
the inflation.
