An apparatus for transmitting data of an image display device includes an image display part equipped with sub-pixels formed between gate lines and data lines, a data driver for driving the data lines of the image display part, a gate driver for driving the gate lines of the image display part, and a timing controller for controlling operations of the data driver and the gate driver, generating a data inversion signal using an transmitted data signal and the next data signal, switching the data inversion signal when the data inversion signal has a logic state successively maintained at least two times, and transmitting one of the next data signal and the inverted next data signal depending on the data inversion signal.