A method for manufacturing an optical device includes the steps of: forming a first multilayer film, including forming a first mirror above a substrate, forming an active layer above the first mirror, forming a second mirror above the active layer, forming a semiconductor layer on the second mirror, and forming a sacrificial layer on the semiconductor layer; conducting a first examination step of conducting a reflectance examination on the first multilayer film; forming a second multilayer film by removing the sacrificial layer from the first multilayer film; conducting a second examination step of conducting a reflection coefficient examination on the second multilayer film; and patterning the second multilayer film to form a surface-emitting laser section having the first mirror, the active layer and the second mirror, and a diode section having the semiconductor layer, wherein the sacrificial layer is formed to have an optical film thickness of an odd multiple of λ/4, where λ is a design wavelength of light emitted by the surface-emitting laser section.