This study aimed to determine the mediating effect of sports confidence on competitive state anxiety and perceived performance basketball game. This study was conducted on 219 Korean basketball players, including 101 men and 118 women who were either high school students (42), university students (96), or professional basketball players (81). The Sources of Sport Confidence Questionnaire (SSCQ), Revised Competitive State Anxiety Inventory-2 (CSAI-2R), and the perceived performance questionnaire was used to measure sports confidence, competitive state anxiety, and perceived performance, respectively. The results showed that self-confidence (β = z 0.552, p < 0.001) and the coaches’ leadership (β = 0.552, p < 0.001) were found to be factors that influenced perceived performance. The perceived performance showed a positive correlation with all the sports confidence subscales and self-confidence of the competitive state anxiety subscales (p < 0.01). However, it showed a negative correlation with cognitive and somatic anxiety (p < 0.01). Sports confidence had a statistically significant mediating effect between somatic anxiety and perceived performance and a statistically significant mediating effect between self-confidence and perceived performance (p < 0.05). It appeared that sports confidence and competitive state anxiety had a statistically significant effect on perceived.