Bulk superconductors are one form of superconducting materials, along with thin films and wires, but from the viewpoint of handling large currents, bulk superconductors are very attractive in that they can handle a large total current at a high current density. In this review, we introduce a new undulator scheme for generating synchrotron radiation by utilizing the high current density of bulk superconductors, and discuss the potential of bulk superconductors in synchrotron radiation technology and its future prospects.