I review the history of the Nichicon’s power supply for accelerators and I show the specifications and experimental data on the Klystron power supply of TRISTAN main ring, the injection bump magnet power supply of SPring-8, and the beam distribution kicker magnet power supply of SACLA which I was involved in. Along with the high performance of the accelerators, higher precision of its power supply has come to be required. We will work on the development of SiC modules, etc., to realize a faster and more accurate power supply for the future in order to contribute to the development of the accelerators.