The article deals with the features of functioning of the system saving mechanism in criminal law; the detailed characteristic of its structure and the contents is given, value of this mechanism for providing with branch integrity is revealed. With this mechanism in criminal law' field the branch system has certain treatment, its elements are put and harmonized. Such structural elements as the principles, the purposes and the objectives of criminal law, branch presumptions and fictions, prejudices, white spaces and conflict rules are carefully investigated. The conclusion is drawn that studied mechanism is the one of   means of self-regulation in criminal law.