A cleaning nozzle is formed at a leading end face of a rigid-endoscope oversheath to cover a rigid endoscope. The cleaning nozzle is connected with a flow path formed in the oversheath so that fluid flowing through the flow path is ejected from an ejection port. The side surfaces of the cleaning nozzle are composed of a relatively hard material, while the upper surface is composed of a relatively soft material. When the flow rate of the fluid ejected from the ejection port is high, the upper surface of the ejection port is widened upward and thereby the direction of ejection of the fluid also changes. The direction of ejection of the fluid can thus be changed by controlling the flow rate.