PROBLEM TO BE SOLVED: To provide an endoscope apparatus and an air/liquid feed nozzle capable of appropriately washing an observation window.SOLUTION: Two first protective walls 248 extend from the edge of a first jet line so as to be substantially continuous with a first side face. The extending direction of the first protective wall 248 is the same as the jet direction of gas or liquid jetted from the first jet line, that is, the first protective wall 248 extends in the jet direction of gas or liquid jetted along the first side face. The extending length of the first protective wall 248 is a length substantially closer to the observation window 251 than a tangent line m of an air/gas feed port 243 at an intersection of a straight line l and the air/gas feed port 243, that is, than a straight line m passing through the intersection of the straight line l and air/gas feed port 243 and orthogonal to the straight line l.
