This paper proposes a new system for 3D object sharing with multiple clients using networks. Our system aims to support group communication across devices over the same 3D object and puts the annotations with augmented reality automatically. In order to keep putting the annotations during the interaction, we apply the vision-based 3D object tracking algorithm which estimates 3D position and pose of the object just by capturing the object with a single RGB camera. By employing the tracking algorithm robust to viewpoint changes and occlusion, we develop the 3D object sharing system with a desktop as a server and a laptop and a smart phone as clients. We conducted the experiments to show the tracking algorithm is tolerant of interaction and can be applied to various objects with texture.