  We propose a new type of radiative seesaw model in which observed neutrino
masses are generated through a three-loop level diagram in combination with
tree-level type-II seesaw mechanism in a renormalizable theory. We introduce a
Non-abelian flavor symmetry $T_7$ in order to constrain the form of Yukawa
interactions and Higgs potential. Although several models based on a
Non-abelian flavor symmetry predict the universal coupling constants among the
standard model like Higgs boson and charged leptons, which is disfavored by the
current LHC data, our model can avoid such a situation. We show a benchmark
parameter set that is consistent with the current experimental data, and we
discuss multi-muon events as a key collider signature to probe our model.
