  A general feature of TeV-scale radiative seesaw models, in which tiny
neutrino masses are generated via loop corrections, is an extended scalar
(Higgs) sector. Another feature is the Majorana nature; e.g., introducing
right-handed neutrinos with TeV-scale Majorana masses under the discrete
symmetry, or otherwise introducing some lepton number violating interactions in
the scalar sector. We study phenomenological aspects of these models at
collider experiments. We find that, while properties of the extended Higgs
sector of these models can be explored to some extent, the Majorana nature of
the models can also be tested directly at the International Linear Collider via
the electron-positron and electron-electron collision experiments.
