The supervision over the legality of concrete administrative acts, carried out in the framework of the administrative procedure, is considered as internal supervision over the work of the public administration authority. The external supervision over the legality of concrete administrative acts, carried out by administrative authorities which are organisationally separate, independent, in no way affected as regards the subject, as well as impartial, is however necessary for the full effect of the principle of legality and at the same time the principle of equality of each individual before the law in the process of decision making in the administrative procedure. It is the judicial supervision over the legality of concrete administrative acts which can be entrusted to the regular courts or the special administrative court. In the Republic of Slovenia the Administrative Court was established in 1997 by the Administrative Disputes Act. In the case of an administrative dispute, this act guarantees the protection of rights and legal interests of individuals, legal persons and other persons, who can be subjects of rights and obligations, against decisions and actions of administrative authorities or in accordance with the act of other authorities of the state, local authorities and bearers of public authority. The Administrative Court is therefore an important creator of the archival material and the definition of the latter is in no respect an easy task.