  We discuss the finite-size effects on the chiral phase transition in QCD. We
employ the Nambu-Jona-Lasinio model and calculate the thermodynamic potential
in the mean-field approximation. Finite-size effects on the thermodynamic
potential are taken into account by employing the multiple reflection
expansion. The critical temperature is lowered and the order of the phase
transition is changed form first to second as the size of the system of
interest is reduced.
