The purpose of this study is to find out whether self-control plays a mediating role in the relationship between adolescents' irrational gambling beliefs and gambling problems. Online illegal gambling is a hot topic as a recent social problem. Variant gambling is permeating deeply in online illegal sites, and this variation induces young people to bet large amounts of money without recognizing that it is gambling by using cute characters they like. Not only adults but also teenagers access illegal gambling sites, fall into gambling, are unable to concentrate on schoolwork, have difficulties with friends, and even commit secondary crimes to pay off gambling debts caused by illegal gambling. In addition, there are cases in which an extreme choice is made after spending a debt through SNS and receiving a collection. As such, the recent increase in gambling problems among adolescents has emerged as a serious social problem. Therefore, in order to find out the seriousness of the youth gambling problem, this study asked 182 general high school and specialized high school students located in ㅇㅇ city, Gangwon-do, where the researcher resides, to ask for permission from the school in advance and allocate time that did not interfere with class time. A total of 59 questions were administered on the Irrational Belief Scale (16 items), the Gambling Problem Scale (9 items), and the Self-Control Scale (34 items). Mediating effects were verified through structural model verification and bootstrap. As a result of the study, there was a significant positive correlation between adolescents' irrational gambling beliefs and gambling problems. This means that the higher the level of irrational gambling belief, the higher the level of gambling problems. In addition, the relationship between self-control and gambling problems, which were set as mediating variables, showed a significant negative correlation. These results show that the lower the self-control, the more likely you are to fall into a gambling problem. Therefore, according to the correlation results of each variable set in this study, it can be predicted that the higher the level of irrational gambling belief, the lower the level of self-control and the higher the level of gambling problems. In addition, it can be predicted that the higher the level of self-control, the lower the level of gambling problems. Self-control was found to partially mediate the relationship between irrational gambling beliefs and gambling problems. These results suggest that when counseling adolescents suffering from gambling problems, it is necessary to lower irrational gambling beliefs and increase the level of self-control. This study is meaningful in revealing the relationship between adolescents' irrational gambling beliefs, self-control, and gambling problems, and recognizing the danger of adolescent illegal gambling problems and the necessity of continuous youth gambling prevention education in schools. Finally, the limitations of this study and suggestions for follow-up studies were made to enable future studies and preemptive responses.