Dark matter, inflation, the neutrino mass-we still have mysteries, and many hypotheses have been proposed to solve these problems. I am interested in examinations of these hypotheses at collider experiments and astrophysical observations. Topics of my recent interest are the collider test of hypotheses in which the Higgs and/or the lepton sectors are extended, and the indications from cosmic-ray observations towards the dark matter problem. I want to see which models are true, and which are not.