The purpose of this study was to create brief self-report scales to assess individual differences in the sensitivity of two behavioral tendencies in delinquents: delinquency approach tendency, and delinquency inhibition tendency. Through factor analysis, as subscales of delinquency approach tendency, we derived two scales: self-centeredness and fun seeking/reward responsiveness, and as subscales for delinquency inhibition tendency we derived three scales: self-punishment responsiveness, punishment-avoidance responsiveness, and inhibition. The reliability and discriminant validity of these scales was confirmed in the form of correlations with alternate measures. Then, using structural equation modeling, we analyzed the effects of both delinquency approach tendency and delinquency inhibition tendency on delinquent behavior. We found that delinquency approach tendency directly increased delinquent behavior, but strong delinquency inhibition tendency did not cause directly decreased delinquent behavior. However, we found that if strong delinquency inhibition tendency weakened delinquency approach tendency, it had an indirect effect of reducing delinquent behavior to a large extent.