There is a stereotyped interpretation of Durkheim's sociology:he had a reified view of social reality. He says, "Indeed, social things are only realized by men: they are the product of human activities." But interpreters have said that they can't easily find such a view in his social theory.<br> On the contrary, this paper will insist that Durkheim certainly had a theory about this mechanism - human activities→social things -. To Demonstrate that, this paper will focus on Durkheim's view of the relation between economy and morality. Of course, we can't avoid an examination of his conception of society The relation between economy and morality is not only a central theme in Durkheim's sociology, but also a strategically important one for our object.<br> By extending an above-mentioned theme, this paper will rearrange Durkheim's sociolgy as a theory of institution. Durkheim's theory had a thory, as follows; institution is produced by human activities and automatizes itself, and finally, it becomes fetters to human beings, i.e. alienation. Furthermore, Durkheim took into account a process of de-alienation of institution.<br> Accordingly, Durkheim's sociology has the same view as Berger = Luckmann's: "In other words, despite the objectivity that marks the social world in human experience, it does not thereby acquire an ontological status apart from the human activity that produced it."