AbstractCyclomaltodextrin glucanotransferase [1,4‐α‐D‐glucan‐4‐α‐D‐(1,4‐α‐D‐glucano)–transferase (cyclizing), E.C.−2.4.1.19] of an alkalophilic Bacillus sp. No. 38‐2 (ATCC 21783), which contains three types of enzymes (acid, neutral, and alkaline enzymes), was immobilized on synthetic adsorption resin. No distinguishing changes in pH or thermal stabilities of enzyme were observed due to the immobilization. Since acid–enzyme activity had disappeared, the optimum pH of immobilized enzyme was 9.0. Optimum temperature for the enzyme activity changed from 50 to 55°C. The enzyme converted starch to cyclodextrins without significant loss of activity under the conditions of continuous reaction for about two weeks by using the column system (60°C at pH 8.0). About 63% of soluble starch solution [4% (w/v)] was changed to cyclodextrins, as tested so far.