  We propose a scenario of brane cosmology in which the Peccei-Quinn field
plays the role of the inflaton and solves simultaneously many cosmological and
phenomenological issues such as the generation of a heavy Majorana mass for the
right-handed neutrinos needed for seesaw mechanism, MSSM $\mu$-parameter, the
right amount of baryon number asymmetry and dark matter relic density at the
present universe, together with an axion solution to the strong CP problem
without the domain wall obstacle. Interestingly, the scales of the soft
SUSY-breaking mass parameter and that of the breaking of $U(1)_{\rm PQ}$
symmetry are lower bounded at $\mathcal{O}(10) {\mathrm TeV}$ and
$\mathcal{O}(10^{11}) {\mathrm GeV}$, respectively.
