Development of thermonuclear fusion research on the earth and the fusion in the universe are reviewed. In this report, the principle of nuclear fusion is explained and the recent activities of the tokamak aiming thermonuclear fusion research are described. The problems towards the thermonuclear fusion research are considered and hot high beta plasma observed in the Jovian magnetosphere is discussed in connection with these problems. As for the fusion in the universe, the nuclear fusion in the sun is explained including other fusion reaction to yield the large mass elements. The hot plasma in the big-bang universe theory is given and the metaphysical meaning that the mankind will manufacture the artificial star is discussed raising the hypothesis of the Maxwell demon.