The relevance of the study of the legal nature and functions of the referendum is conditioned by the increasing dynamics of development of direct democracy in the developed countries and the needs to legalize it in constitutional and legal norms to ensure stability in society. The purpose of this paper is to define the legal nature of the referendum in the context of the theory of constitutional law. The research methodology is built on the comparison of institutional and instrumental features of the referendum. The materials of the legal practice of the Federal countries of Western Europe are investigated, having a tradition of direct democracy and the practice of its legislative regulation. The basis of the study is constitutional norms about the referendum of the Constitution of Germany, Switzerland, Austria and Belgium, as well as quantitative data on referenda in those countries. In the result of the study of the legal nature of the referendum the evident instrumental purposes of direct democracy are justified: legitimation, restraint, institution, self-government and political arbitration. Also a conclusion is made about the instrumental function of the referendum in modern Federal countries of Western Europe. The obtained results of the study are important in theoretical terms – for the development of the definition of a referendum, understanding of its legal nature and functions, and in practical terms - for legislative activities and public discussions about ways of development of democracy in certain public conditions.

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