A fixing device for endotracheal intubation of rodents is provided. The fixing device includes: a bed configured to place a rodent thereon; a support member attached to an upper end portion of the bed in a transversely movable manner and supporting a gas supply pipe through which an anesthetic gas is supplied to the nose of the rodent; and a fastening member configured to fix the support member to the upper end portion of the bed after an end portion of the gas supply pipe is aligned with the nose of the rodent.