An object of the present invention is to provide an optical fiber bundle having high adhesive strength at an end, and an endoscope using the optical fiber bundle. Another object of the present invention is to provide a method of producing the optical fiber bundle having high adhesive strength at an end. An embodiment of the present invention provides an optical fiber bundle including a bundle of optical transmission elements, each of which includes a fiber including a core made of a first glass and a cladding made of a second glass and covering an outer periphery of the core, and a covering layer covering the outer periphery of the cladding. The covering layer includes an alkyl group having 1 to 7 carbon atoms and not being fluorine-substituted. The alkyl group is bonded to the cladding via a siloxane bond.