  The problem of quantum fluctuations of the chiral condensate due to
next-to-leading contributions is investigated. Meson contributions to the
chiral condensate are calculated in the Nambu--Jona-Lasinio model with the
analytical (dimensional) regularization in a framework of the mean-field
expansion. The pion contribution can be significant, while the sigma-meson
contribution is small in the regime of physical values of the model parameters.
Non-pole contributions are also estimated and found to be small.
