[en] There have been many reports about radiation from thundercloud since 1930's. The radiation within and the upper part of thundercloud were observed by balloon, air plane and satellite after 1980's. The some examples of observations out and in the country are described. CGRO (Compton Gamma Ray Observatory) observed γ-ray generated from more than 30 km upper from the earth. In Japan, radiation indicator increased in winter. The environmental radiation monitors indicator in the ground of Monju increased at one time. The radiation strength increased with increasing the electric field strength within thundercloud. Radiation behavior in thundercloud was estimated by Monte Carlo method. The charge distribution of thundercloud in summer and winter, the electric field strength of thundercloud (three poles structure) in winter and the total photon flux were calculated. (S.Y.)