an optical waveguide positioning substrate having a simple construction and which is easy to maintain , and a positioning method using this substrate , which can be applied to various types of optical component having different numbers of optical waveguides . an optical waveguide positioning substrate has an array body provided with an optical component placing part for aligning an optical component having an optical waveguide and a plurality of light - emitting parts , illuminating / extinguishing of each of which can be freely selected , disposed at an end of the array body in the length direction of the optical component and aligned in the width direction of the optical component .