The procedural action is the central point on which the invalidation is based, because the invalidation is a penalty that results from the invalid procedural action that lacks of one condition or more than one condition of its validity. Since the detention, which is the deprivation of the defendant’s liberty for a certain period until the completion of the investigations, it is considered one of the procedural actions that might be invalidated. Therefore, the legislator stipulated some conditions of the detention, some of them are objective conditions, and some of them are formal conditions. All of these conditions are necessary for the validity of the detention, and they must be adhered under penalty of invalidation. This is because detention conflicts with some legal principles that the legislator has been keen to adhere as guarantees of individual liberty, such as the presumption of innocence and the origin of human freedom, because of the risk of detention that impacts on the social, psychological and physical condition of the defendant, as this case needs guarantees reassuring the defendant to prevent the arbitrary authority in using this detention, and because the detention is one of the investigation activities that have legal justifications in terms of serving the interest of the investigation. The Jordanian legislator did not specifically address the issue of the invalidation of detention as a result of non[1]performance of one or more of these conditions that are necessary for its validity, which stipulated by the legislator but without stipulating the penalty for violating them. However, the failure to perform these conditions results in the invalidation.