A mounting apparatus of the present invention mounts an optical element on a wiring board that has, on the rear surface thereof, a reflecting mirror section of an optical waveguide. The mounting apparatus is configured to have: a mounting table, which supports the wiring board on a holding region; a mounting nozzle, which holds the optical element, and which mounts the optical element on the wiring board; a light source, which emits light that passes through/illuminates the reflecting mirror section through the holding region; an image pickup device, which picks up a light transmission image of the reflecting mirror section; and a control device, which determines the mounting position of the optical element on the basis of the light transmission image. High-density mounting is achieved without providing an exclusive light introducing section for alignment for mounting the optical element.