We present an interactive 360-degree tabletop display system for collaborative work around a round table. Users are able to see 3D objects on the tabletop display anywhere around the table without 3D glasses. The system uses a visual perceptual mechanism for smooth motion parallax in the horizontal direction with fewer projectors than previous works. A 360-degree camera mounted above the table and image recognition software detects users' positions around the table and the heights of their faces (eyes) as they move around the table in real-time. Those mechanics help display correct vertical and horizontal direction motion parallax for different users simultaneously. Our system also has a user interaction function with a tablet device that manipulates 3D objects displayed on the table. These functions support collaborative work and communication between users. We implemented a prototype system and demonstrated the collaborative features of the 360-degree tabletop display system.