A driving device is provided for a cathode fluorescent lamp (CCFL) circuit, comprising a voltage generator outputting a driving voltage and a controller coupled thereto. The controller directs the voltage generator to output a first voltage exceeding a working voltage of the CCFL to initialize the CCFL. When brightness of the cold cathode lamp tube exceeds a working brightness of the CCFL, the controller directs the voltage generator to decrease the driving voltage gradually so that the brightness of the CCFL equals the working brightness. The controller stops decreasing the driving voltage when the driving voltage equals the working voltage.