The Preliminary Division is a court unit that has important functions and powers within the structural links of the International Criminal Court and provides a link between criminal investigation, prosecution and trial procedures. In fact, this Department filters out whether the criminal act that took place during the period before the criminal case reached the Judicial Department falls within the jurisdiction of the Court, and such important nuances, and transfers the so-called "finished product" to the Judicial Department.

The BCM stage of the proceedings has a very important role to play in the termination of the proceedings and in the issuance of the relevant decision (sentence). This stage involves an inseparable process, with the Prosecutor referring the case to the Preliminary Chamber, referring it to the Court of Appeals, and finally appealing to the Chamber of Appeals against the decisions and proceedings of those chambers.