An optical device includes an optical waveguide, an optical element, and a resin layer disposed between the optical waveguide and the optical element. The resin layer is formed of a photocurable material alone or in combination with a thermosetting material and includes an optical interconnect for optically connecting the optical waveguide and the optical element. The optical interconnect has a higher refractive index than a region of the resin layer around the optical interconnect. A method for producing the optical device includes providing the photocurable material between the optical waveguide and the optical element, partially irradiating the photocurable material with light to form the optical interconnect, and secondarily irradiating the overall photocurable material with light to cure the overall resin layer.