A distal end portion successively provided from an insertion part distal end of an endoscope is provided with an air supply and water supply nozzle, an observation window, and illumination windows, and are formed with mutually parallel first and second flat surfaces. The surface of the observation window is disposed at the same position as the second flat surface. An inclined surface that connects the first flat surface and the second flat surface together is formed at a position that faces the air supply and water supply nozzle. Fluid guide surfaces are formed on both sides of the inclined surface. The fluid guide surfaces incline toward the illumination windows. A fluid jetted from the air supply and water supply nozzle impacts against the inclined surface, spreads to the observation window, and is guided to the fluid guide surfaces, and flows to the illumination windows.
