Niobium becomes superconductor at highest temperature in metals. Therefore this is used for superconductive acceleration cavity in next generation particle accelerators. Chemical Polishing (CP) is required in the cavity manufacturing process to meet required performance. SAN-AI PLANT contributes to clear the required performance of the cavities by CP and cleaning technologies. The cavities will be used in such as International Linear Collider (ILC) and Energy Recovery Linac (ERL) at KEK.