An electronic amplifying substrate, including: a glass base material having an insulating property; conductive layers formed on both main surfaces of the glass base material; and a plurality of through holes formed on a lamination body of the glass base material and the conductive layer, wherein an electric field is formed in the through hole by a potential difference between both conductive layers during application of a voltage to a surface of the conductive layer so that an electron avalanche amplification occurs in the through hole, and an insulation part is formed on at least one main surface of the glass base material, with one of the end portions of the insulation part formed to surround an opening part of the through hole of the glass base material, and the other end portion formed in contact with the end portions of the conductive layers.