  We investigate the stability of an Fermi ball(F-ball) within the
next-to-leading order approximation in the thin wall expansion. We find out
that an F-ball is unstable in case that it is electrically neutral. We then
find out that an electrically charged F-ball is metastable in some parameter
range. We lastly discuss the allowed region of parameters of an F-ball, taking
into account the stability of an F-ball and results of experiments.
