Disclosed is a curvature-adjustable endotracheal tube. The curvature-adjustable endotracheal tube includes: a hollow cylindrical tube body configured to maintain a patients airway and a curvature-adjusting wire configured to allow an operator to freely adjust the curvature of the tube body to correspond to the curvature of the patients airway into which the tube body is inserted. Both ends of the curvature-adjusting wire are respectively fixed to a distal portion and a proximal portion of the tube body such that the distal portion is pulled and bent when the proximal portion is bent by the operator.