Based on Robert W. Corrigan’s unique interpretation of hubris, this study defines Existential Hubris as the inner form of Tragedy. Corrigan considers hubris, which conventionally means arrogance or pride, the 모드니 예술, 제4호 - 72 - special quality in the mentality of the tragic heroes. This study develops Corrigan\'s concept of hubris into the new term, Existential Hubris, and defines it as the essence of tragedy. Existential Hubris means the tragic hero\'s mental quality that makes the hero desire to place himself on the center of the universe and determine his own existence refusing any transcendental principle or deity. Defining the mental quality as the inner form of tragedy, this study explores the essence of tragedy. Also, this study distinguishes the form of tragedy from the form of melodrama through the concept of Existential Hubris and examines how Albert Camus\'s and Jean-Paul Sartre\'s dramas illustrate the concept. Finally, this study explains that tragedy is a unique product of Western philosophical tradition that distinguishes human subject from the universe. The concept of Existential Hubris makes the category of tragedy more defined and limited. Such a definition of the form will make the artistic term, tragedy, used in a more precise way.