To provide a dimming DC voltage device having simple construction for correcting a switching delay time for a photocoupler to generate dimming DC voltage corresponding to a delivered PWM signal independently of the frequency of the PWM signal delivered from a dimming signal delivery device.

The dimming DC voltage output device 100 includes the photocoupler PC1 for outputting a voltage change to the secondary side corresponding to a voltage change on a primary side, the primary side and the secondary side being insulated from each other, a dimming signal delivery part 110 connected to the primary side of the photocoupler PC1 for delivering the PWM signal, and a DC voltage generation part 120 for inputting secondary side voltage corresponding to the PWM signal output to the secondary side by the photocoupler PC1, moderating the falling gradient of the input secondary side voltage, generating DC voltage corresponding to the voltage whose gradient is moderated, and outputting the generated DC voltage to a control signal generation part 210.