<p>In present Japan, we are facing the problems of energy policies, for example the public opinions abandoning for nuclear power generation, slower growth for installing renewable energy and decreasing population and domestic demand. Considering future energy supply structure for Japan, the importance of natural gas is increasing instead of oil and coal regarding to energy security and environmental protection. So I focus the structural plan of importing natural gas and analysis for its risks according past cases, Shawaryn projects, and make the risk analysis tree on its consideration.</p>