Although the negative effects of overconfidence are more likely to be mentioned in the literature, some researchers have argued that the benefits of overconfidence may outweigh its costs. We attempted to explore the positive effects of overconfidence in competitive situations. We had participants compete against fake opponents who were overconfident and then measured their competitive performance in two studies. In Study 1 we examined the effects of overconfidence on competitive performance in a competitive situation and the possible mechanism for this overconfidence. In Study 2 we investigated the characteristics of the performance in a competition after a mismatch between the level of confidence and the fake opponent's actual competence was revealed. Our results indicated that overconfident individuals tend to be perceived as more competent and more likely to benefit in the process of competition. Even after a mismatch between the level of confidence and the real competence was revealed, the overconfident individuals were not punished in that they made as much money as the less overconfident and still got higher competence ratings. Together those studies suggested that overconfidence has its advantages in competitive situations.