This paper is an attempt to discuss Arthur Miller, especially in The Crucible as a social tragedian, who has until now been studied and estimated mainly as a tragic playwright in critical areas and the history of the American dramas, especially the social background, which examines how Miller reflected tragic social aspects such as the Holocaust in Europe during World War Ⅱ and irrational McCarthyism in America in the 1950s in his works. Also, he has influenced modern American and European playwrights on the creative structures of his works, and especially extended the scope of themes to a number of social issues through many of his plays. Miller was influenced by not only Greek tragedies, especially Aristotle`s tragedy but also the atheistic existentialists such as Sartre, Camus, and Foucault. However, he made much of not their theories, but human life itself. He established the idea that not `What should I know?` but, `What should I do?` is important in his social dramas. His main concerns about relationships between individuals and the modern industrial society make him more absorbed in political and social issues. As a representative of modern and tragic American playwrights, Miller has been regarded as a complex thinker because of being variously called as a moralist, a humanist, an atheistic existentialist, a feminist, a social psychologist and so on from others. Therefore, it focuses on the background of Miller`s tragic thoughts about society and concentrates upon the tragedy of moral humanism. On a concrete level, it tries to decipher the source of Miller`s tragedy, the background of psycho-social existentialism, and the distinctive features of Miller`s social tragedy. Arthur Miller, one of the 20th century American authors, is a very important figure in the modern literary world. From his early works to his latest, he found topics in his neighborhood and published works with which many people can sympathize, based on his own experiences. He mainly focused on the relationship between humans and society, and was interested in exposing social irregularities. Therefore, he is valued as a representative social playwright.