Juggling is one of tasks involving skillful dynamic manipulation, and visual information is essential to perform juggling. We achieved a two-ball juggling task with our high-speed robotic hand-arm system which had three general-purpose fingers and high-speed vision system. But it could not afford enough long operation time for juggling because the trajectory was not optimized. Therefore this algorithm often caused miss of catching the ball. In this study, we work on the improvement of the robot's trajectory at the juggling. We get the 3-dimensional hand position in human ball juggling by a 3D sensor. As a result the characteristics of human juggling is obtained. Based on the motion analysis, we make the throwing motion whose orbit is a circle including internal and external motion. We are successful in the throwing and catching motion by a new program.