In a backlight device that adjusts brightness by turning on/off switches provided in parallel to respective LEDs, deterioration and breakage of the LEDs, variability in brightness, and flickering are suppressed. In at least one embodiment, a backlight device includes: an LED array including a plurality of LEDs connected in series and bypass switches (transistors) provided in parallel to the respective LEDs; a bypass switch control circuit for switching between an on state and an off state of the bypass switches; an FET having a drain terminal connected to the LED array and a source terminal grounded; a constant current drive control circuit for applying a constant current to the LED array by applying a predetermined voltage to a gate terminal of the FET; and a capacitor whose one end is connected to the gate terminal of the FET and whose other end is grounded.