The article gives general aspects of superconducting alternator, which is noticed as an application of superconductivity on electrical machine recently. A careful consideration is required to design the machine composed of some unique parts. Electrical characteristics of superconducting machine have been found considerably different from conventional machines owing to lack of iron core. Mainly, superconducting alternator has been considered to be useful as large turbo-generator for central power station, but it is expected to be useful as electrical ship propulsion system and as synchronous condensor also. Finally, present status of development is reviewed.