Heavy ion accelerators adopt diverse designs and accelerating structures based on the requirements of the users whereas the structure for a single-particle such as proton or electron accelerator is rather well defined by the energy and the current of a beam. The advent of superconducting technology has been a major driving force in pushing the energy frontier for all kinds of accelerators. The core technologies of superconducting accelerators are in the fields of cryogenics, superconducting magnets and radio-frequency acceleration structures. Some details of technological advancements in superconducting accelerators will be presented. While the Large Hadron Collider and the International Linear Collider have been developed for high-energy physics, heavy-ion accelerators especially linear accelerators for high-current beams in the energy range of 1 GeV have been recently developed for new nuclear-physics projects to produce wide-range radioisotope beams. The applications of heavy-ion beams on the other hand have been diversified from nuclear science to biomedical and material researches. The applications usually ask for low-energy beams, and require compact and economical design. The superconducting technologies are often good fits for such demands.