For the study I gave my students a task “Handspring on mat.” The purpose of my research is to find out “effects which the self-confidence in the task has on achievements of the their performance and self-efficacy.” The summary of my research is the following; 1. Achievement level depending on the confidence in movement performance To find out the difference of achievement level, the students were divided in three groups on accordance with the test result of confidence. 2. Achievement level depending on success or failure of a performance To find out effects the success or failure of a performance has on achievement level, students were divided into two groups ; a success group and a failure group. 3. Attribution factors which has effects on the confidence of the success group The relative difficulty of a task has little effect on the three groups which have different confidence in the success groups of the performance. 4. Attribution factors which has effects on the confidence of the failure group The relative difficulty of a task has little effect on the three groups which have difference in the failure group of the performance. The student\'s efforts to the task are not different from the three groups. Fortune has on effect on all the three groups. In conclusion, all attribution factors relative difficulty of a task, effort, ability and fortune has no effect on the accomplishment in the failure group of the performance. So teachers should try to develop efficient teaching method to encourage students to intensify their motive of their accomplishment.