STATUS REPORT OF SUPERCONDUCTING RF ACTIVITIES IN KEK

In KEK there are three groups which concern with superconducting rf. The superconducting accelerating cavity group and the superconducting crab cavity group belong to KEKB (KEK B-factory). The L-band superconducting cavity group works for domestic and international collaborations of KEK. Introduction on these groups and their activities is presented in this paper. Main part is devoted for the introduction of crab cavities, which are new type superconducting rf cavities and are planned to install into KEKB to increase luminosity.