Seeing the characteristic of juvenile delinquency that is happening in our country, it is being indicated a qualitative change like owering age, grouping, and truculence, and a point as saying of being high in recidivism, as well as a quantitative rise in cases like violence, rip-off, and sexual assault by adolescents. What the juvenile delinquency is important is being further so in a sense of which many people among adult criminals have experience of having committed a crime for the first time during childhood. In our society, a sight is strong that sees criminal problem as the one in the individual dimension. As for juvenile delinquency of growing with being expanded into lower age group, the socio-environmental approach is effective rather than an individual adolescent. This study examined about a concept and characteristics of adolescents and juvenile delinquency, and about characteristics of treatments in juvenile correctional institution, and suggested the improvement plans for treatments such as first, plan of treatment within the facility, second, plan of halfway treatment, third, community treatment, based on the present status of treatments for juvenile convicts.