The present application discloses an illuminating device and a method for driving the illuminating device. The illuminating device comprises: an LED illuminating module; a mains supply operation module, comprising an LED driving unit; and a ballast operation module, comprising a simulation filament unit, a first detection unit, a second detection unit, a switch unit, a first start unit and a second start unit; wherein when the illuminating device is in a mains supply operation mode, the LED driving unit is used for driving the LED illuminating module; when the illuminating device is in a magnetic ballast operation mode, the first detection unit detects a voltage signal or frequency signal of the simulation filament unit and outputs a first detection signal, and after receiving the first detection signal, the first start unit enables the switch unit to be in a conducting state and drives the LED illuminating module; and when the illuminating device is in an electronic ballast operation mode, the second detection unit detects a voltage signal or frequency signal across both ends of the illuminating device and outputs a second detection signal, and after receiving the second detection signal, the second start unit enables the switch unit to be in a conducting state and drives the LED illuminating module.