  We discuss some details for the model proposed in Ref. \cite{aks-prl}, in
which neutrino oscillation, dark matter, and baryon asymmetry of the Universe
can be simultaneously explained by the TeV-scale physics without introducing
very high mass scales. An exact discrete $Z_2$ symmetry is introduced, under
which new particle contents (a real singlet scalar field, a pair of charged
singlet scalar fields and TeV-scale right-handed neutrinos) are assigned to
have odd quantum number, whereas ordinary gauge fields, quarks and leptons, and
two Higgs doublets are even. Tiny neutrino masses are generated at the three
loop level due to the exact $Z_2$ symmetry, by which stability of the dark
matter candidate is also guaranteed. The extra Higgs doublet is required not
only for the tiny neutrino masses but also for successful electroweak
baryogenesis. We discuss phenomenological properties of the model, and find
that there are successful scenarios in which above three problems are solved
simultaneously under the constraint from current experimental data. We then
discuss predictions in such scenarios at ongoing and future experiments. It
turns out that the model provides discriminative predictions especially in
Higgs physics and dark matter physics, so that it is testable in near future.
