Appratus and method for driving lcd

An apparatus for driving an LCD device and a driving method thereof are provided to prevent glare in a screen due to an abrupt gray scale conversion by driving continuously the same frames whose gray scale values are converted linearly. An apparatus for driving an LCD(Liquid Crystal Display) device includes a frequency converting unit(210), a frame determining unit(220), and first and second gray scale converting units(230,240). The frequency converting unit converts frame frequency and outputs continuously the same frames. The frame determining unit determines whether an input frame is a still image or a moving image frame and outputs a still image informing signal or a moving image informing signal according to the determination. The first gray scale converting unit converts the gray scale values of the pixels of frames from the frequency converting unit through one gray scale transition. The second gray scale converting unit converts the gray scale values of the pixels of frames from the first gray scale converting unit through linear gray scale transition steps in response to the still image informing signal or moving image informing signal.