A drainage device for discharging a liquid retained in a palpebral fissure to the outside of the palpebral fissure includes a hook portion that is bent into a hook to be hooked on a lid margin or a medical drape and comes into contact with the liquid in the palpebral fissure or overflowing from the palpebral fissure to form a start point of a flow path for the liquid, and a body portion that extends from the hook portion and discharges the liquid guided by the hook portion. The distal end of the hook portion is formed into a spatula shape. The body portion includes an abdominal portion and a tail portion and discharges the liquid after arrival thereof at a surface of the tail portion by making the liquid run along a gap between a lid margin side surface of the abdominal portion and the lid margin or the medical drape.
