An optical fiber which, at an optical fiber connecting end having a plurality of voids around the periphery of a core, has a light-permeable substance, such as a resin or glass whose refractive index is lower than that of quartz type substances, filled in the voids adjacent to the connecting end. The invention encompasses a substrate bonded to a coating cured, at least in part, cationically by a light having a wavelength in a range of 100 nm to 1200 nm and intensity in a range of 0. The underlayer deactivation layer is formed on the first insulation film at a side surface of the hole, and exposes the wiring at a bottom surface of the hole.