A data driving device of the present invention comprises: a first channel processing unit for charging a first load capacitor of a first data line; a second channel processing unit for charging a second load capacitor of a second data line; a channel MUX for connecting the first channel processing unit to the first data line and connecting the second channel processing unit to the second data line; a first switch for selectively connecting the first data line and the second data line; a charge sharing line in which charges charged in the first and second load capacitors are shared with each other when the first switch is turned on; a control unit; and a comparator, which compares the output voltage of the charge sharing line with a reference voltage so as to output a comparative voltage that indicates whether bonding of the data driving device and a display panel is defective.