An endoscope includes light emitting devices arranged in the distal end portion of its insertion unit, and at least one elongated heat-radiating member. One end of the radiating member is arranged in the vicinity of the light emitting devices and the other end is arranged in a predetermined position adjacent to the proximal end of the insertion unit. In observation using the endoscope, a decrease in the amount of illumination rays or the occurrence of image noise can be prevented, the decrease and the noise being caused due to heat generated by LED illumination lights arranged at the distal end of the insertion unit. Therefore, observation can be performed for a long time in good conditions.
