We have been participating RoboCup middle size league by using omnidirectional mobile robot with omnidirectional vision sensor. Ball handling technique as well as vision processing technique is the important issue of RoboCup robot. This time we designed and developed a small-sized ball kicking mechanism that enables loop shoot. We used CAD and CAE software for obtaining some design parameters of the kicking mechanism. Next, we measured the kicking capability by experiments and evaluated its performance. The trajectory of the kicked ball is not as good as we have expected by CAE, but enough satisfactory for the real RoboCup games.