  The chiral phase structure of the Nambu-Jona-Lasinio/Gross-Neveu model at
finite temperature T and finite chemical potential \mu is investigated using
(Wilsonian) Non-Perturbative Renormalization Group (NPRG). In the large N_c
limit, the solutions of NPRG with various cutoff schemes are shown. For a
sufficiently large ultra-violet cutoff, NPRG results coincide with those of
Schwinger-Dyson equation and have little cutoff scheme dependence. Next, to
improve the approximation, we incorporate the mesonic fluctuations. We
introduce the auxiliary fields for mesons, and then derive NPRG equation for
finite N_c. The chiral phase structure on (T,\mu) plane beyond the leading of
1/N_c expansion is investigated in the sharp cutoff limit. N_c dependence of
chiral phase diagram is obtained.
