Lighting device

This lighting device is provided with: a plurality of light sources; a power supply circuit that generates a power supply voltage on the basis of a voltage outputted from an external power supply; and a control circuit that is driven by means of the power supply voltage. The control circuit detects reduction of the power supply voltage, and controls the lighting states of the light sources on the basis of the detection. The power supply voltage is supplied to all of or some of the light sources. 照明装置包括：多个光源；基于从外部电源输出的电压生成电源电压的电源电路；和由所述电源电压驱动的控制电路。所述控制电路检测所述电源电压的降低，基于该检测控制所述多个光源的点亮状态。所述多个光源的整体或部分被供给所述电源电压。