The velocity of the center of gravity of the pivot leg and the ground reaction force of the stride leg during windmill pitching are critical for ball speed. The aim of this study was to investigate jump ability in relation to the velocity of the center of gravity of the pivot leg and the ground reaction force of the stride leg. Seven female softball pitchers performed windmill pitching and various jump tests: countermovement jump, standing long jump (SLJ), rebound jump (RJ), and one-step approach single-leg vertical jump (AVJ). The results obtained were as follows. 　1） No significant relationship between the ball speed during windmill pitching and jump ability was observed in any of the jump tests. 　2） The velocity of the center of gravity of the pivot leg was significantly correlated with SLJ and RJ ability. 　3） The vertical and horizontal negative impulses (ground reaction force) during windmill pitching were significantly correlated with those in the AVJ. 　These results demonstrated that the velocity of the center of gravity of the pivot leg and the ground reaction force of the stride leg—which, as demonstrated in previous studies, are crucial in determining the ball speed during windmill pitching—were correlated with jump ability. Moreover, the relationship between jump ability and the velocity of the center of gravity of the pivot leg and that between jump ability and the ground reaction force of the stride leg differed.