THE OFFENDERS, RANGED IN AGE FROM 16 TO 19. AS A RESULT OF DETAILED OBSERVATION AND TESTING OF SUBJECT BACKGROUND AND PERSONAL CAPABILITIES, IN TURN REFINED BY STATISTICAL ANALYSIS, AN ATTEMPT WAS MADE TO CORRELATE VARIOUS PERSONALITY AND BACKGROUND TRAITS WITH DELINQUENT BEHAVIOR. IN TERMS OF BACKGROUND, FACTORS HAVING A HIGH DEGREE OF CORRELATION WITH DELINQUENT BEHAVIOR INCLUDED BROKEN FAMILIES, FREQUENT MOVES OF RESIDENCE, FREQUENT CHANGES OF OCCUPATION, AND MEMBERSHIP IN SOCIALLY LESS DESIRABLE GROUPS, SUCH AS GANGS. PERSONALITY TRAITS WHICH CLOSELY CORRELATED WITH THE DEGREE OF DELINQUENT BEHAVIOR AND TENDENCIES INCLUDED VIOLENCE, AGGRESSIVENESS, SELFCENTEREDNESS, WEAK SELF-DISCIPLINE, LOW LEVELS OF AMBITION, INSTABILITY OF EMOTIONS, INCONSISTENCY, ARBITRARY ACTIONS, AND PERSONAL VANITY. PERSONALITY FACTORS SHOWING A LOW CORRELATION WITH DELINQUENT BEHAVIOR INCLUDED COOPERATIVENESS, MATURE EMOTIONAL BEHAVIOR, AND CONSTRUCTIVE ACTIVITY. NUMEROUS STATISTICAL TABLES AND GRAPHS APEAR THROUGHOUT THE ARTICLE. A SHORT BIBLIOGRAPHY, AS WELL AS A COPY OF THE BASIC MJPI SURVEY FORM USED, ARE APPENDED. --IN JAPANESE