A method of manufacturing an optical waveguide having a core and a clad. The method includes forming a first clad by applying a resin on a substrate and curing the resin, applying a core material between a recessed mold which has a recess having a shape identical to a shape of the core and the first clad which is provided on the substrate, curing the core material applied, thereby forming a core pattern having a shape corresponding to that of the recess, and peeling the recessed mold from the core pattern and the first clad.