PURPOSE: To eliminate a patient anxiety about liquid run-out of instillation.

CONSTITUTION: A colored floating valve 3 of a spherical shape is put into an instillation vessel 2 provided in the middle of an instillation tube 1. An outflow port 4 for an instillation liquid L is made hermetically closable by this floating valve 3. This outflow port 4 is provided with a translucent housing part 5 of a width capable of concealing the entire part of the floating valve 3. The liquid feed stops automatically when the instillation liquid runs out according to this constitution. In addition, the liquid run-out is identifiable by whether the color of the float is visible or not and, therefore, the patient's anxiety about the liquid run-out is eliminated.