The purpose of this study was to clarify the social power of students who were ranked highly in the "School Caste" (class status ranking) and the determinants of these students' social power. One hundred and sixty-three university students completed the questionnaire, which asked them to recall high-ranking students within their junior high school class's "School Caste." The questionnaire comprised questions regarding the social power (referent power, attraction power, punishment power, expert power) and external and internal characteristics (appearance, character, communication skill, academic ability, and attitude) of one male and one female high-ranking student. The results of cluster analysis using social power showed the difference by sex of types of high-ranking students within the "School Caste." Regarding male students, there were three types: those with high attraction power scores; high punishment power scores; and high scores for all social power. Regarding female students, there were four types: those with all high scores for social power except punishment; those with average scores for all social power; those with high punishment power; and those with low scores for all social power except attraction. The results also revealed the existence of a "high punishment power group," who had high scores for punishment power and low scores for the other three types of social power, among both high-ranking male and female students. Multiple regression analysis showed the same determinants of social power for male and female students: determinants of expert power were academic ability and character; one determinant of attraction power was communication skill; and one determinant of punishment power was appearance. The results also showed the following difference between male and female students: for high-ranking male students, the determinants of referent power were academic ability and attitude, but as for female students, the determinant was character.