A lens adaptor includes a first mount formed at one side of the lens adaptor and coupled to a body mount of a lens changeable photographing apparatus, a second mount formed at the other side of the lens adaptor, to which a lens mount of a lens is coupled, an aperture lever arranged to contact an aperture pin of the lens when the lens mount of the lens is coupled to the second mount, and an aperture ring capable of moving the aperture pin of the lens via the aperture lever, due to rotation, when the lens mount of the lens is coupled to the second mount.