There are more damages from collision at sea because of the multiple reasons of sea conditions. For the purpose of avoiding collision at sea, Internaitonal Regulations for Preventing Collision at Sea, 1972 as an international convention is in force having the nature of international navigating law. According to the nature of the convention and the principle of legislation of the convention, not only it has the preventing nature on collision but it is a basic rules to make clear the faults of collision between vessels by the admiralty court in the developed maritime countries. Since there is no so much case law on it in this country and not to fixed the legal theory to define the faults of collision in civil law as per the above convention, the further study of the civil liability on collision based upon the above convention shall be recognized in the principle of fair of the civil law.