An optical fiber mounting method that mounts a plurality of optical fibers on a substrate includes: bundling the optical fibers together with a bundling member; adjusting a height of the bundling member from a surface of the substrate or an angle of inclination of the bundling member relative to the surface of the substrate; bringing end faces of the optical fibers bundled with the bundling member into contact with end faces of optical waveguides on the substrate, the optical waveguides respectively corresponding to the optical fibers; and bonding the optical fibers to the substrate, in a state where the end faces of the optical fibers are in contact with the end faces of the optical waveguides.