Arnold Gehlen is considered to be one of the original sociologists. Thus, he was an editor of the first German postwar textbook on sociology. Gehlen shared scientific worldview and thought that the human being is a result of the evolution of the living world. He often referred to the searching of “missing link” of Louis Leakey and the works of other paleontologists. However, the interconnection between human and animal, according to his position, is considered wrongly by the followers of idealism and religion and by the majority of evolutionists. In this article we will speak about Gehlen’s social theory, which is trying to overcome drawbacks of evolutionists’ and idealists’ theories by showing the role of action in human’s development as a biological kind and describing the main schemes of social action and its regulation.