An endoscope is provided and includes a flexible insertion tube； a distal end assembly provided at an end of the insertion tube； and a cooling medium tube provided in the inside of the insertion tube, and connected to the distal end assembly. A cooling medium for cooling the distal end assembly is introduced through one of the insertion tube and the cooling medium tube, and discharged through the other of the insertion tube and the cooling medium tube. Since the endoscope is configured such that the cooling medium directly contacts with a heating element or a conductor through which the heat of the heating element is conducted, the cooling effect of the front end portion of the endoscope is improved.
