This study aims to analyze the authority of the Harbor Master in the prosecution and resolution of cases in the field of shipping based on Law Number 17 of 2008 concerning Shipping. This research is normative legal research with the consideration that this research departs from the analysis of legislation. The approach method used in this study is the legislative approach, conceptual approach and case approach. Legal material collection techniques with library studies. The method of analysis uses interpretation. Based on the results of the study, it can be explained that Harbor Master has the authority to carry out sea patrols, carry out instant chases, stop and inspect ships in the sea and conduct investigations. The procedure for prosecuting cases is under the Supervisory Coordinator. If an administrative violation occurs, it will be delegated to the Shipping Court, and if a criminal offense is found, it will be delegated to the Public Prosecutor. Based on the description above, for the future, it needs to be regulated to support the authority of the Harbor Master in law enforcement and enforcement in the field of shipping of the Head Office of the Directorate General of Sea Transportation, to give the Office of the harbor Master each province or region (representative), both from the facility special investigation and budget to support the enforcement and investigation process of a criminal case in the field of shipping, which so far has only been limited to the Class I Master harbor office.