A purpose of this article is to examine a ambivalence of the public sphere and mass media seen through Jurgen Habermas's writings consistently. Such a ambivalence have structure of the reproduction of a normative concepts in cycling with norms and realities. In Habermas's literatures, it seems that the ambivalence of the public sphere and mass media can be arranged for four phases. First, the concept of the public sphere extracted as an ideal type from a historical process of Western European society is applied to analysis of realities and becomes ambivalent things. Second, lifeworld as a new normative concept is set. Third, it has faced realities of the colonization of the lifeworld by the system, and the concepts of self-organizing and mutual-subjectivity are introduced newly. Forth, thus civil society as the normative concept is made. In other words, it can be said that Habermas is grasping the public sphere and mass media as an interaction between norms and realities. It is caused by his recognition that caught the public sphere and mass media as ambivalent things without abandoning these potentialities. For the mass media, it is possible to play the role which activates a public debate, if managed by democratic systematization and normative self-understanding. However, it works to depoliticize public communication if the information sorted out according to the command of a system is processed. It is asked a reconfirmation and embodiment of the normative principles for mass media. That is democratic systematizing so that it may function as an arena after confirming principles for serving civil society independently of the state and the capital.