The purpose of this article is to verify the existence of ambivalence in “Fear of Success” and the factor which cause it. Two isvestigation were carried out by undergraduate students (first investigation: 161 females and 193 males. second investigation; 139 females and 118 males). Questionnairs are composed of fear of success scale, which is almost the same as that used in many other studies, and scenario study, which mesures how positively or negatively people consider their own and other people's success in a success situation. The results express ambivalence clearly in both females and males. And sex difference was qualitative rather than quantitive. Among females 'interests in others' was important factor for ambivalence, but among males 'littie need for superiority' was important factor for ambivalence.