To improve the yield of light-source elements, to enhance their productivities, and to reduce their costs by adjusting the brightnesses of each light-source element in the case of the manufacture of a light-source board.

The light-source board connects resistance elements in a parallel relationship to each light-source element connected by a required connection form on a wiring board. Regarding the light-source board, the resistance elements are trimmed or cut by laser beams on the basis of a result measuring the brightnesses of each light-source element. Consequently, the brightesses of each light-source element can be adjusted, and the yields of the light-source elements are made better than conventional devices in which the light-source elements as off-specification brightnesses are wasted, thus improving the productivities of the light-source boards and reducing the costs of the light-source boards.