The law finds it difficult to apprehend the notion of the family because, on the one hand, to the absence of legal definition of this term, and on the other hand, the diversity of existing family situations. However, the necessity of guaranteeing the family rights of the people imposes the research for its understanding and for its rationalization. It is by the apprehension of the notion of the family as an indefinite but abstract notion that this thesis aims to identifying its irreducible element, that is its conceptual unity. In order to do this, the judicial judge has been designated as the effective observer of the family notion's conceptual unity and it is true because of the structure of the jurisdictional act by which he achieves his duty. It will be shown that, when the judge decides to create a family bound or to recognize a family bound created abroad, he identifies the family notion's conceptual unity in the concept of family bound and highlights its constituent elements, as well as the way they are connected.