We study the theory beyond the Standard Model of particle physics. The Standard Model has been quite successful in explaining the behaviour of the elementary particles at the electroweak scale about 100GeV. However, there are several problems unsolved in the Standard Model. For example, the Standard Model cannot explain what the dark matter of the Universe is, what mechanismgenerates the asymmetry between matter and anti-matter in the early Universe, how the tiny neutrino mass is generated, and so on. Some issues are strongly related to cosmology so that we also study the history of the Universe.