The notary has the authority to legalize the deed under the hand requested by the parties. But often in the deed under the hand contains elements of acts against the law. This study aims to describe the responsibilities of a notary to his profession as a general official making an authentic deed, and to describe the notary's responsibility for an underhand agreement that contains elements of illegal acts that have been legalized. The method used in this article is normative juridical, which is a secondary data analysis with statute approach and conceptual approach that has descriptive analytical reasearch spesifications. The results of research in this article, namely: first, the notary's responsibility towards his profession as an official of an authentic deed is only limited to the formal form of an authentic deed, not to the contents of the deed, every act carried out by a notary can be held accountable if there is a violation committed and the act can cause harm for the parties. Second, the notary liability for an underhand agreement that contains elements of illegal acts that have been legalized, that is, the notary is not responsible for the contents of the deed under the hand even though there is a clause in the act against the law.