The purpose of the present invention is to provide a low-cost optical circuit board with which it is possible to align with a fiber array while mounted on a package and reduce size without affecting the main circuit section, and to also provide an optical device and an alignment method. This optical circuit board has a loop-back circuit mounted thereon, which returns aligning light in the vicinityof a fiber array connection end to the fiber array. Since an aligning loop-back circuit can be thus formed in an optical waveguide pattern, production costs do not increase in comparison to conventional optical circuit boards. Aligning light that links from an optical fiber to an aligning port of the optical circuit board is returned to the optical fiber via the loop-back circuit. Therefore, alignment is possible using said returned light. In other words, alignment is possible while mounted on a package without having to install a light-reflecting film or mirror.