A superconducting (SC) rotating-gantry for carbon radiotherapy was developed. This isocentric rotating gantry can transport carbon ions with the maximum energy of 430 MeV/u to an isocenter with irradiation angles of over +-180 degrees, and is further capable of performing three-dimensional raster-scanning irradiation. The combined-function SC magnets were employed for the rotating gantry. The SC magnets with optimized beam optics allowed a compact gantry design with a large scan size at the isocenter; the length and the radius of the gantry are approximately 13 and 5.5 m, respectively, which are comparable to those for the existing proton gantries. The total weight of the gantry is estimated to be approximately 300 tons. Construction as well as installation of the SC gantry was completed by the end of September, 2015. Beam commissioning subsequently begun since October, 2015, and carbon beams, as accelerated by the HIMAC upper synchrotron, having kinetic energy of between 430-48 MeV/u were successfully transported with the SC gantry to the isocenter. Presently, we are further designing a next-generation compact SC gantry as well as a SC synchrotron as a future project. In this talk, the recent progress of the SC rotating-gantry as well as new developments for the future project is presented.