‘A sport event’ is an expression which embraces a sport meeting and surrounding social phenomenon. A sport event here is confined as a mega sport event in contemporary capitalist society. Researches are required to clarify the merits and the demerits of the mega sport events. In the first half of this manuscript, “the social history and sport event” will be discussed. A primitive society was “the birth age of sports”, because sports were born as training for hunting. Sports were equally enjoyed by all people of the society. Then, the ancient slavery age, especially ancient Greece, emerged. As typically seen to ancient Olympics, the age was “a birth age of sport events”. feudalism society was dominated by religions. Since religions had a common belief that “Spirit dominates over body”, three body demands, exercise, sex and appetite, were very important subjects of religious training. Therefore, sport events disappeared from the medieval times of Europe. However, capitalist society required new movement cultures, such as sports (Britain), gymnastics (Sweden, Germany) and martial art (Japan) etc. And sport events were re-born in capitalist society. In the second half of this manuscript, “capitalism and sport events” will be discussed. Especially, the Olympics as a representative of mega sport events will be analyzed from the financial viewpoint and historically. The Olympics developed its gigantism and authority from the 1970s, with combining the global strategy of multinational corporations and the infrastructure building of Olympics host cities. The maladies (the sacrifice of the social welfare, environmental destruction etc.) became very severe. IOC and the Olympics have been pressured to make a sustainable mega sport event.