Using a sample of 116 Japanese men who had been placed under parole/probationary supervision or released from prison, the present study examined standardization, reliability, and validation of the Japanese Criminal Thinking Inventory (JCTI) that was based on the short form of the Psychological Inventory of Criminal Thinking Styles (PICTS), a self-rating instrument designed to evaluate cognitive patterns specific to criminal conduct. An exploratory factor analysis revealed that four dimensions adequately captured the structure of the JCTI, and the resultant 17-item JCTI demonstrated high internal consistency. Compared with the Japanese version of the Buss–Perry Aggression Questionnaire (BAQ), the JCTI showed a favorable pattern of criterion-related validity. Prior criminal environment and drug abuse as the most recent offense also significantly correlated with the JCTI total score. Overall, the JCTI possesses an important implication for offender rehabilitation as it identifies relevant cognitive targets and assesses offender progress.