Light from each LED is applied to an integrating sphere (reference object), and a light amount calculator calculates light reflected from the integrating sphere. Calibration data, in which source control signals applied to the LEDs are associated with amounts of the light from the LEDs emitted in response to the source control signals, respectively, is generated. A maximum amount of the light from each LED is set in accordance with a predetermined light amount ratio. Based on the maximum light amount, an nth light amount which corresponds to a brightness step n is set. With reference to the calibration data, the source control signal which corresponds to the nth light amount is set as the source control signal for the brightness step n. A light control table is generated by associating the source control signal for the brightness step n with a brightness command signal for the brightness step n.