To evaluate the effectiveness of the new victim participation systems, we examined whether the use of these systems had an effect on the confidence of the families of victims about the criminal justice system. The results of a questionnaire survey revealed that victims who participated in their criminal court cases had more confidence in the criminal justice system and were more accepting of the court decisions. Moreover, the present study examined the process of victims' confidence in criminal justice based on the value-expressive theory of procedural justice. In particular, the assumption was confirmed that the victims' feelings of expressing opinions resulted in their increased confidence in criminal justice through their confidence in the judges and their acceptance of court decisions.