  We investigate the quark condensate of the QCD vacuum within the instanton
vacuum model. We calculate the meson-loop contributions to the dynamical quark
mass and quark condensate to ${\cal O}(1/N_c)$-, ${\cal O}(m/N_c)$-, and ${\cal
O}((m\ln m) /N_c)$-order corrections. We find that the meson (especially pion)
loops provide substantial contributions to the dynamical quark mass and as a
result to the quark condensate. The results indicate that the $1/N_c$
corrections should be reconsidered in the systematical way. The present results
are consistent with those from chiral perturbation theory.
