A light guide for endoscopes is constituted by a plurality of multimode optical fibers, of which at least a portion is bundled. The light guide propagates illuminating light beam that enters from a first end facet thereof to a second end facet thereof, to emit the illuminating light beam onto a portion to be observed. The light guide includes: a light input portion formed by the bundled plurality of multimode optical fibers; and a light output portion formed by the bundled plurality of multimode optical fibers. At least one of the light input portion and the light output portion is shaped in a tapered shape, while the number of multimode optical fibers at the light input portion and the light output portion are the same as that at other portions of the light guide.