Omnidirectional driving gear is a proprietary technology designed and possessed by Tadakuma laboratory in Yamagata University. It is a next generation gear mechanism having two degrees of freedom on one gear surface. We have newly developed a free form omnidirectional driving gear by combining flat and convex arc surfaces. A v-grove rail guide mechanism is adopted to enable stable horizontal motion along the planar gear surface and rotational motion round the convex gear surface. With this setup, we were able to design and operate an omnidirectional driving gear corresponding to a free-form surface. Although this mechanism adopt rail and cantilever structure, it was confirmed by experiments that its performance is comparable to that of the conventional flat plate omnidirectional driving gear. In this design, the motion range is small and is limited to the shape of the curvature. We plan to come up with a 2nd prototype design which will be more flexible and that will be able to achieve sophisticated motion path trajectories.