The Mega-Float, a very large offshore floating structure, is regarded as material for structuring of social capital in the new future. Experiments using an actual-scale model 1 000 m long were carried out by Technological Research Association of Mega-Float under Director-General Kentaro Aikawa, Mitsubishi Heavy Industries, Ltd. (MHI) Senior Corporate Advisor. Examples of Mega-Float use include as an airport and as a rescue base for disaster. MHI is conducting unique studies and development in antiwave performance, joining technology for floating units, environmental assessment, very-long-term endurance, and the pursuit of total design by synthesizing respective technologies considered to be keys for realizing practical Mega-Float use.