The so-called adjustment of the investigative powers of the prosecution and the police brought major changes to the roles and functions of the prosecution and police. The key to this adjustment is that the police are given primary investigative power and can conduct investigations independently. Even if there is no suspicion of a crime, the police can close the investigation on their own. On the other hand, the prosecution can directly investigate only six major crimes. Moreover, it is only possible to control the police investigation results later. In addition, the police organization was divided into the national police and local police. The purpose of this study is to examine how the adjustment of investigative powers affects the juvenile justice procedure. To this end, I will first examine and review the current laws and regulations related to the juvenile justice procedure. Next, we will examine what measures can be taken to improve the juvenile case.