In a conventional driving circuit, it has been inefficient and difficult to measure, classify, and rank (Vf) characteristics of a light emitting element that is in a bare-chip state. According to the present invention, a semiconductor-type light source is made of four light emitting chips (41 to 44) that are in a bare-chip state, the light emitting chips being randomly mounted on a board (3) without classifying (Vf) characteristics in advance. As the resistors, opening resistors (R2, R4, R6) and trimming resistors (R1, R3, R5) are disposed in parallel and then are connected in series to the four light emitting chips. Values of the resistors are adjusted so that a predetermined set current value or luminous flux value is reliably obtained with respect to the four light emitting chips. As a result, the present invention is capable of efficiently and easily mounting the four light emitting elements (41 to 44) and the resistors (R1 to R7) on the board (3).