  Radiative neutrino mass models have interesting features, which make it
possible to relate neutrino masses to the existence of dark matter. However,
the explanation of the baryon number asymmetry in the universe seems to be
generally difficult as long as we suppose leptogenesis based on the decay of
thermal right-handed neutrinos. Since right-handed neutrinos are assumed to
have masses of O(1) TeV in these models, they are too small to generate the
sufficient lepton number asymmetry. Here we consider Affleck-Dine leptogenesis
in a radiative neutrino mass model by using a famous flat direction LH_u as an
alternative possibility. The constraint on the reheating temperature could be
weaker than the ordinary models. The model explains all the origin of the
neutrino masses, the dark matter, and also the baryon number asymmetry in the
universe.
