A data-driving apparatus of an electro-luminescence display panel includes a display panel receiving a current signal to display an image, and a data driver having a plurality of current sink data drive parts in order to supply data to the display panel based on a constant current, wherein the current sink data drive part comprises a current sink data drive integrated circuit for supplying the data to the display panel based on the constant current, and a reference current supply/path part for supplying the constant current to the current sink data drive integrated circuit and, at a same time, supplying the same constant current to an adjacent current sink data driver in a cascade circuit configuration.