This study analyzes ‘the social’ which is the most problematic concept of Hannah Arendt from the standpoint that Arendt’s idea of the social is the critique of liberalism preempting Michel Foucault’s biopolitics. Arendt’s major works trace how liberal governmentality (obsession with life) through markets in capitalist society resulted in totalitarian violence. In her studies, the social is the most important concept placed at the center. And, the understanding of her critique of classical political economy must be preceded in order to understand Arendt’s concept of the social. The classical political economists in the 18th century assumed the market’s spontaneous order through civil society as a kind of common good. In other words, they believed the pursuit of individual interest became the interest of the whole, and economic interdependence created the social order. However, Arendt regards the phenomenon that the social dominates the public sphere as a threat of ‘life’ to the ‘world’. This is also the subject Foucault later pursued. Arendt and Foucault grasp politics which has been reduced to a series of technologies that manage security and security of the population in the inevitable of life as the core of modern politics. This study explores some important aspects of the social implied by Arendt’s critique of classical political economy, and proves that Arendt’s theory still tells us important things through comparison with Foucault.