To provide a 21st century type undesea structure similar to a wooden turtle type submarine devised by the General Yi Sunsin in the Korean period in Korea, advantageous in cost and time in comparison with conventional undersea tunnels.

This invention structures a method of constructing an undersea structure saved in migration length, time and the construction cost by connecting an island to an island, a peninsula to an island, and a land to a land for convenient life of people. The undersea tunnel in Genkainada open sea, one of recent subjects, has difficult problems because it is necessary to excavate rocks deep undersea. On the other side, this invention can be constructed undersea independently of contents of the rock and the earth's crust, and not only in Genkainada but also in various areas such as Bering Strait, Gibraltar Strait and Taiwan Strait, roads and railroads can be used in the undersea structure to provide good life over the whole of the earth. This invention shows that human beings trying space has unlimited possibility.