A comparative study between Group A (those who have attempted suicide) and Group B (those without attempt) among 999 of senior (second grade) boys and girls was conducted to investigate how such factors as personality, environment, etc. are related to their suicidal attempts. Emotional stability and social maladjustment were noticed in Group A as to the personality difference, and no marked difference was discriminated as to the environmental difference observed in family construction in this study. Farther reports will be made in II and III under the same study.