A device for fixing a laboratory rodent for inhalation anesthesia includes: a body including a cavity into which at least a part of a rodent including the nose of the rodent is insertable and a gas supply pipe inserted into the cavity for supplying an anesthetic gas to the rodent, the gas supply pipe including a fixing part on an end portion thereof for fixing incisors of the rodent and an opening formed at a position forward from the fixing part for discharging the anesthetic gas. Therefore, the position of the opening relatively to the nose of the rodent may be constantly maintained.