PROBLEM TO BE SOLVED: To provide an endoscope capable of removing water droplets that easily move to an illumination window.SOLUTION: An air/water sending nozzle 33, a treatment tool outlet 38, an observation window 45, a pair of illumination windows 46, 47, and a groove part 55 are arranged on the flat surface 50 of an insertion part of an endoscope. The air/water sending nozzle 33 selectively injects air and washing water from an injection opening 72 toward the observation window 45. The groove part 55 is formed long in a direction crossing a direction from the observation window 45 toward the air/water sending nozzle 33. In the groove part 55, one end 55a is connected to the treatment tool outlet 38. The other end 55b is located on a line E extending from one end 72a of the injection opening 72 opposite from the treatment tool outlet 38 in the injection direction of fluid. Since water droplets of the washing water which do not reach the observation window 45 are captured by the groove part 55, air injection prevents the water droplets from being sent to the illumination window 46.
