A method of manufacturing an optical waveguide includes: forming a first reflective bump and a second reflective bump, which have inclined surfaces formed on sides opposite to each other and which are disposed with a predetermined distance in-between, on an upper side of a conductive carrier; polishing the surfaces of the first reflective bump and the second reflective bump; forming a core between the first reflective bump and the second reflective bump; stacking an upper cladding over the upper side of the carrier to cover the first reflective bump, the second reflective bump, and the core; removing the carrier; and stacking a lower cladding over a lower side of the upper cladding. Forming reflective bumps on a conductive carrier, and polishing the reflective bumps to form inclined surfaces, can reduce lead time and can provide a high degree of freedom in design.