There is provided a method of manufacturing a conductive layer of in a signal transmission substrate. The method includes sewing conductive thread in sheet-like material having an insulating property so as to form one of a plurality of low resistance regions using the conductive thread in a high resistance region formed by the sheet-like material, moving the conductive thread from an end point of a previously sewed low resistance region to a start point of a low resistance region to be sewed subsequently, repeating the sewing and moving steps to form the plurality of low resistance regions in the high resistance region, and forming a plurality of holes in the conductive layer by press working so that an electrical component attached to at least one of the plurality of holes is able to transmit a signal between neighboring ones of the plurality of low resistance regions.