  The Ginzburg-Landau formalism is constructed for Fermi superfluidity based on
the 2n-body condensation in parallel with the usual Ginzburg-Landau formalism
for the Cooper pair condensation. By this formalism, the transition temperature
of the 2n-body condensation is given compactly by the zero of coefficient of
the quadratic term in the 2n-body condensed order parameter without counting
complicated Feynman diagrams for the 2n-body condensation susceptibility. It is
shown that the 2n-body condensed state is stabilized in the intermediate- or
strong-coupling regime against the BCS state based on the Cooper pair
condensation. This theory is applied to the case of the possible superfluid
state of cold atomic gases such as $^9$Be and $^{173}$Yb; the quartet state is
possible in the former case, while the sextet state is expected in the latter
case. It is predicted that the $^{173}$Yb atomic gas so far attained satisfies
the condition for the sextet condensed state to be realized.

Superconductivity