In this paper we propose a successive gait-transition method for a quadruped robot to realize omni-directional static walking. The gait-transition is successively performed among the crawl gaits and the rotation gaits while the feet are held in a common position before and after the gait transition. The gait-transition time is reduced by carefully designing the foot position of the crawl gait and the rotation gait while limiting the feet in rectangular reachable motion ranges. Experiments were executed to show the validity and the limitation of the proposed gait-transition method.