We developed the process for the production of cyclodextrins from unliquefied corn starch in a membrane bioreactor. Cyclodextrin Glycosyltransferase (CGTase) is inhibited by cyclodextrins. In order to decrease product inhibition, cyclodextrins were filtrated using ultrafiltration system. Optimum conditions for the production of cyclodextrins in a membrane bioreactor were; initial substrate concentration : 7%. enzyme loading : 350 U/g-starch. substrate milling time : 3 hr. substrate feeding rate : 5.75-6 g/L/hr. In optimum conditions, amount of cyclodextrins produced per enzyme increased about 2.85 times in a membrane bioreactor compared to batch. The ratio of β-cyclodextrins produced in a membrane bioreactor showed a 9% increase over batch reactor.