PACS numbers: 14.60.Pq, 14.60.St, 14.80.Cp, 12.60.Fr.-- 4 pages including 3 figures.We propose an extended version of the standard model, in which neutrino oscillation, dark matter, and baryon asymmetry of the Universe can be simultaneously explained by the TeV-scale physics without assuming unnatural hierarchy among the mass scales. 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 guaranteed. The extra Higgs doublet is required not only for the tiny neutrino masses but also for successful electroweak baryogenesis. The model provides discriminative predictions especially in Higgs phenomenology, so that it is testable at current and future collider experiments.This work was supported, in part, by Japan Society for the Promotion of Science, Nos. 1945210 and 18034004, and the MEC project FPA 2004-02015, the Comunidad de Madrid project HEPHACOS (P-ESP-00346), and the European Network of Theoretical Astroparticle Physics ILIAS/ENTApP (RII3-CT-2004-506222).