A method for manufacturing an optical-semiconductor device, including forming a plurality of first and second electrically conductive members that are disposed separately from each other on a support substrate; providing a base member formed from a light blocking resin between the first and second electrically conductive members; mounting an optical-semiconductor element on the first and/or second electrically conductive member; covering the optical-semiconductor element by a sealing member formed from a translucent resin; and obtaining individual optical-semiconductor devices after removing the support substrate.