An endoscope includes an insertion portion； a first projecting portion； a second projecting portion； an illumination window disposed on an outer peripheral surface side of the first projecting portion, the illumination window being disposed about an axis along a longitudinal axis direction of the insertion portion, the illumination window having a light emitting surface from which an illumination light for illuminating an inside of a subject is emitted in a direction which includes a sideward direction of the insertion portion； and a mask configured to restrict sideward emission of the illumination light from the illumination window, wherein the mask has a shape inclined with respect to the longitudinal axis direction so as to increase a quantity of the illumination light emitted toward the second projecting portion from a distal end side toward a proximal end side of a distal end portion of the insertion portion.
