Human cognitive and psychological characteristics should be considered for design of user interfaces. In this study, the relationship between the sense of agency and the task performance was examined through an experiment. The experimental task was target-searching by controlling a joystick. In the experiment, temporal delay of visual feedback was set to indirectly control the participants' sense of agency. The experimental results demonstrated that there is a negative correlation between the degree of sense of agency and the reaction time. Based on the result, we concluded that the sense of agency plays a key role for the improvement of the cognitive performance.