A light guide for endoscopes constituted by a plurality of bundled optical fibers is formed such that it is flexible at portions where flexibility is required, and such that the durability thereof is improved. The light guide for endoscopes is constituted by a plurality of bundled optical fibers, for propagating an illuminating light beam that enters from a light input end facet thereof to a light output end facet thereof, to emit the illuminating light beam onto a portion to be observed. The light guide includes: a plurality of comparatively large diameter optical fibers and a plurality of comparatively small diameter optical fibers which are provided at the side of the light guide toward the light output end facet thereof. Each of the comparatively large diameter optical fibers is connected to a plurality of the comparatively small diameter optical fibers.
