In this seminar, the status of the light sterile neutrino searches and whether there is good and reasonable physics pictures for the neutrinos are discussed. The light sterile neutrino is non-weak interactive neutrino, and it was introduced to explain the results of the LSND experiment. The idea to exist the particle which is sensitive to gravity but not to strong, electromagnetic and weak forces are interesting, however, currently only LSND and MiniBooNE experiments provided positive results. This seminar reviews the status of the sterile neutrino searches in the world, which includes the JSNS2 experiment (J-PARC Sterile Neutrino Search at the J-PARC Spallation Neutron Source). The experiment aims the direct confirmation or refute the LSND results. It will be started from the end of JFY2018.