PROBLEM TO BE SOLVED: To provide a cooling device for an endoscope that facilitates observation by securing sufficient visibility through an observation window in a high-temperature environment and can thereby prevent the efficiency of examination from deteriorating.SOLUTION: There is provided the cooling device for an endoscope that cools a distal end part of an insertion part 2 of an endoscope 1, where an observation system is disposed, by causing cooling fluid to flow. The cooling device includes: a compressor 12 for supplying the cooling fluid a heat-resistant sheath 11 that forms a cooling flow passage where the cooling fluid supplied from the compressor 12 flows by being fitted to the outer circumferential side of the insertion part 2 a transparent observation window 11a which is disposed at the distal end part of the heat-resistant sheath 11 so as to prevent the cooling liquid from leaking out of the heat-resistant sheath 11 and to make the object of observation observable from the observation system and a nozzle 25c which is arranged near the observation window 11a and jets fluid for jetting toward the observation window 11a.
