2018 年 53 巻 7 号 p. 527-540
Baseball pitchers can throw various types of breaking balls such as curve, slider, forkball or split-finger fastball and knuckleball. Therefore, for batting practice, a baseball ball launching device which can launch various breaking balls is required. However, most of the commercially available devices can only launch breaking balls whose rotation axis is perpendicular to the traveling direction. In this research, a baseball ball launching device which can launch a breaking ball whose rotation axis is parallel to the traveling direction is refined so that breaking balls with arbitrary rotation axis can be realized. The rotation axis of the breaking balls launched by the refined device are observed by using a high-speed camera. Through trajectory observation of experiments, the reproducibilities of the braking balls launched by the refined device are confirmed.