<；P>；PROBLEM TO BE SOLVED: To provide a method by which a fish can be safely and simply anesthetized in a fish farm and the like, and an anesthetizing device. <；P>；SOLUTION: An anesthetizing aqueous carbonic acid solution containing dissolved carbon dioxide having concentration effective for anesthetizing the objective fish and dissolved oxygen having concentration required for living the fish is prepared in advance by dissolving carbon dioxide supplied from a carbon dioxide feeding source 12 and oxygen supplied from an oxygen feeding source 12a in a source water supplied by pump 11 in an anesthetizing aqueous carbonic acid solution-producing means 18. The anesthetizing aqueous carbonic acid solution is fed into an anesthetizing water tank 19 in which the anesthetization is performed and the fish is anesthetized by putting the fish in the anesthetizing water tank 19. As the fresh anesthetizing aqueous carbonic acid solution containing certain amounts of dissolved carbon dioxide gas and dissolved oxygen is always fed to the anesthetizing water tank 19, accidental and sudden death of the fish during anesthetization caused by decline in water quality and lack of oxygen by secretions is prevented. <；P>；COPYRIGHT: (C)2008,JPO&INPIT
