  The Higgs inflation scenario is an approach to realize the cosmic inflation,
where the Higgs boson plays a role of the inflaton. In the minimal model, it
would be difficult to satisfy theoretical constraints from vacuum stability and
perturbative unitarity. These problems can be solved by considering multi-Higgs
models. In this talk, we discuss a Higgs inflation scenario in a radiative
seesaw model with an inert doublet, which originally has been proposed to
explain dark matter and neutrino masses. We study this model under the
constraints from the current data, and find parameter regions where additional
scalar bosons can play a role of inflatons. They satisfy the current data from
neutrino experiments, the dark matter searches and also from LEP and LHC. A
unique phenomenological prediction appears in the mass spectrum of inert scalar
bosons. We show that this scenario is challenging to be tested at the LHC, but
would be well testable at the International Liner Collider by measuring
endpoints of energy distribution of a two jet system from decay processes of
the inert scalar fields produced via pair production.
