Cosmic ray flux is an important factor to response to solar activity. Its profile shows the decreasing shape by interaction of enhanced interplanetary magnetic field structure. When the solar eruptions such as solar proton events by flares arrive at the Earth, the profile of cosmic ray flux changes to sharp increasing shape at the ground neutron monitor. The former is well known as “Forbush decrease”, while the latter is known as “Ground level enhancement”. Cosmic ray working group began neutron monitor research in the early 2000s. At first, our group focused on the interaction between solar wind/interplanetary magnetic field and cosmic ray particles. The main topics are simultaneity of Forbush decreases, anisotropy of diurnal variation, relationship between solar proton events and ground level enhancements and so on. The first of neutron monitor by our group has installed at Daejeon in October, 2011. Another neutron monitor has been installed at Jang Bogo in Antarctica in December, 2015. The observational data by both neutron monitors have registered at Neutron Monitor Database (NMDB, http://www01.nmdb.eu/data/) on April, 2018. I introduce the brief installation of neutron monitor at Jang Bogo and the scientific achievements in cosmic ray research.