  The charged Fermi gas with a small Lande-factor $g$ is expected to be
diamagnetic, while that with a larger $g$ could be paramagnetic. We calculate
the critical value of the $g$-factor which separates the dia- and para-magnetic
regions. In the weak-field limit, $g_{c}$ has the same value both at high and
low temperatures, $g_{c}=1/\sqrt{12}$. Nevertheless, $g_{c}$ increases with the
temperature reducing in finite magnetic fields. We also compare the $g_{c}$
value of Fermi gases with those of Boltzmann and Bose gases, supposing the
particle has three Zeeman levels $\sigma=\pm1, 0$, and find that $g_{c}$ of
Bose and Fermi gases is larger and smaller than that of Boltzmann gases,
respectively.
