A process for economically producing a large amount of camptothecin which is the starting compound for irinotecan hydrochloride and various camptothecin derivatives, characterized by involving the following steps (a) and (b): (a) the step of hydrolyzing 9-methoxycamptothecin or a natural material containing 9-methoxycamptothecin; and (b) the step of converting the 9-hydroxycamptothecin obtained in the step (a) into a 9-o-perfluoro(lower alkyl)sulfonyl or 9-o-phenyltetarzolyl derivative followed by the hydrogenolysis into camptothecin.
