There is provided an endoscope in which the generation of heat at a front-end portion is reduced.An endoscope includes an imaging system； and, an illumination system, wherein the illumination system includes a light guide and at least one illumination lens, and the imaging system includes an objective lens unit and an image pickup element, and when a direction along a long side of the image pickup element is let to be a first direction, and a direction along a short side of the image pickup element is let to be a second direction, the illumination system is disposed at a position shifted in the second direction with respect to the imaging system, and the endoscope satisfies the following conditional expressions (1), (2) and (3)1.35<；A (1)1<；LH/LV (2)1.5<；(rV−LV)/(rH−LH)≦3.17 (3)where,A denotes a value calculated by the following expression when an aspect ratio long side:short side of an area of the image pickup element corresponding to a display image range is let to be H:VA=H/V, LH denotes a dimension corresponding to the first direction of an end surface on an illumination lens side of the light guide,LV denotes a dimension corresponding to the second direction of the end surface on the illumination lens side of the light guide,rH denotes an outer-diameter dimension corresponding to the first direction of the illumination lens, andrV denotes an outer-diameter dimension corresponding to the second direction of the illumination lens.
