The purpose of this study was to develop ego developmental crisis state scale (ECS) during adolescence and its ego developmental crisis state by means of ECS. In a first study, 302 students from 12 to 23 years of age completed questionnaires on the ego developmental crisis state during adolescence. Their responses were factor analyzed. Consequently, ECS for adolescents, containing 26 items of self examination problems and 24 items of self aware symptoms, was constructed. The reliability of ECS was discussed with respect to alpha coefficients and test-retest correlations. In a second study, 279 students from 12 to 23 years of age were administered with ECS. The main results were as follows. 1) Senior high school students scored higher on self examination problems score and self aware symptoms score than any other groups. 2) It was found that self examination problems score were related to self aware symptoms score. 3) While there were differences between grades on self examination problems score, there were no differences between males and females, or between grades on self aware symptoms score. There were also differences between males and females, and between grades on the score of subscales of the ECS. These results gave some therapeutic suggestions for the psychotherapy of adolescents.