PROBLEM TO BE SOLVED: To provide a heat absorption structure of an insertion portion of an endoscope which can efficiently absorb heat of an image pickup device by using a fluid which can be sprayed to the outside of the endoscope.SOLUTION: A heat absorption structure of an insertion portion of an endoscope includes: an objective lens system 42 which is provided inside a distal end portion 18 of an insertion portion 12 extending from an operation unit 11 to the front and is exposed on a surface of the distal end portion metallic supporting members 26 and 46 provided inside the distal end portion both of an image pickup device attachment hole 46 located immediately behind the objective lens system, and a fluid hole 31 that is independent from the image pickup device attachment hole and has a front end opening communicating the outer space of the distal end portion, on the supporting members an image pickup device 49 provided in the image pickup device attachment hole for capturing an observation image that transmits the objective lens system and internal conduit lines 58 and 59 which are provided inside the insertion portion, are connected with the fluid hole, and supply a cooling fluid to the fluid hole.
