Status and development of superconducting cavity for KEKB

After successful test of 500 mA (Max 573 mA) electron beam at TRISTAN Accumulation ring (AR) using a prototype superconducting cavity, more than 4 superconducting cavities will be installed in High Energy Ring (HER) of KEK B-factory. The initial 4 superconducting cavities are almost same as the prototype one. The tests and results of the critical components of superconducting cavity system is described.