Our Constitution stipulates the principles of due process (Article 12 (1)) and the presumption of innocence (Article 27 (4)) as in order to maximize the freedom of the person, which is a prerequisite for guaranteeing all basic rights. In particular, the principle of presumption of innocence is the principle that in a criminal trial, a suspect or defendant should be treated as innocent until a guilty verdict is finalized, and the disadvantages should be limited to the minimum necessary. Therefore, since the principle of presumption of innocence is a principle that limits the restraint of the person itself, investigation and trial in criminal procedures are, in principle, required to be conducted in a state of detention. Accordingly, personal restraint in criminal procedures should be exceptionally used only in cases where it is deemed impossible to achieve the purpose of criminal proceedings because it is impossible to effectively respond to crimes by means other than restraint. If alternative means other than restraint are possible, a system should be prepared to select alternative means according to the principle of proportionality.
 Based on these constitutional values, our Criminal Procedure Law has established the principle of investigation without detention (Article 198 of the Criminal Procedure Act) and trial without detention in the operation of the person restraint system. Regulations on the system of personal detention and release of persons under arrest have been revised. However, looking at the reality of the operation of the arrest and release system, it is questionable whether these institutional devices are properly contributing to the realization of constitutional values and principles of criminal procedure law. For example, there is not much difference in the rate of release by adjudication against detention compared to before the introduction of the arrest warrant review system, and the operation of the bail system has also increased the possibility of realizing the principle of trial without detention by introducing various conditions for bail after the 2007 revision of the Criminal Procedure Act. Despite this, the court arrest rate has increased, and the rate of permission for bail has decreased rather than before the introduction of various bail conditions. This trend in statistics leads us to infer that the detention review and bail system, contrary to the purpose of the revision efforts to lower the arrest rate, do not function as practical control means to curb unnecessary detention and prevent the prolongation of detention. Therefore, it is necessary to find a plan that can actually work as an ex post means to realize the constitutional value of the current detainee release system.