An organic light emitting display device comprising: a display panel configured to include a plurality of sub-pixels, each sub-pixel including an organic light emitting diode (OLED) configured to emit light according to a data current (Ioled) based on a data voltage (Vdata); a memory configured to accumulate and store data (Adata) displayed by each of the plurality of sub-pixels as accumulated data (Adata); and a panel driver comprising: a degradation compensation gain value calculator configured to calculate a degradation compensation gain value for increasing or decreasing a luminance of each sub-pixel at every degradation compensation point of a plurality of degradation compensation points, based on an accumulated data reference value (Ref1, Ref2, Ref3) of each degradation compensation point and the accumulated data (Adata) of each sub-pixel stored in the memory, a data modulator configured to generate modulated data (Mdata) of each sub-pixel by modulating input data (Idata) of each sub-pixel in accordance with the degradation compensation gain value of each sub-pixel, a data accumulator, and a data driving circuit configured to convert the modulated data (Mdata) into the data voltage (Vdata), characterized in that the panel driver further comprises: a degradation weight reflector configured to calculate a degradation weight, based on a grayscale value of the modulated data (Mdata) of each sub-pixel, and reflect the degradation weight in corrected modulated data (Mdata') of a corresponding sub-pixel to correct the modulated data (Mdata), wherein the degradation weight reflector is configured to differently set the degradation weight according to the grayscale value of the modulated data so that degradation characteristics of sub-pixels having the same accumulated data are the same, wherein the data accumulator is configured to accumulate the corrected modulated data (Mdata') of the corresponding sub-pixel and store the corrected modulated data (Mdata') obtained by accumulation in the memory as the accumulated data (Adata). a display panel configured to include a plurality of sub-pixels, each sub-pixel including an organic light emitting diode (OLED) configured to emit light according to a data current (Ioled) based on a data voltage (Vdata); a memory configured to accumulate and store data (Adata) displayed by each of the plurality of sub-pixels as accumulated data (Adata); and a panel driver comprising: a degradation compensation gain value calculator configured to calculate a degradation compensation gain value for increasing or decreasing a luminance of each sub-pixel at every degradation compensation point of a plurality of degradation compensation points, based on an accumulated data reference value (Ref1, Ref2, Ref3) of each degradation compensation point and the accumulated data (Adata) of each sub-pixel stored in the memory, a data modulator configured to generate modulated data (Mdata) of each sub-pixel by modulating input data (Idata) of each sub-pixel in accordance with the degradation compensation gain value of each sub-pixel, a data accumulator, and a data driving circuit configured to convert the modulated data (Mdata) into the data voltage (Vdata), a degradation compensation gain value calculator configured to calculate a degradation compensation gain value for increasing or decreasing a luminance of each sub-pixel at every degradation compensation point of a plurality of degradation compensation points, based on an accumulated data reference value (Ref1, Ref2, Ref3) of each degradation compensation point and the accumulated data (Adata) of each sub-pixel stored in the memory, a data modulator configured to generate modulated data (Mdata) of each sub-pixel by modulating input data (Idata) of each sub-pixel in accordance with the degradation compensation gain value of each sub-pixel, a data accumulator, and a data driving circuit configured to convert the modulated data (Mdata) into the data voltage (Vdata), characterized in that the panel driver further comprises: a degradation weight reflector configured to calculate a degradation weight, based on a grayscale value of the modulated data (Mdata) of each sub-pixel, and reflect the degradation weight in corrected modulated data (Mdata') of a corresponding sub-pixel to correct the modulated data (Mdata), wherein the degradation weight reflector is configured to differently set the degradation weight according to the grayscale value of the modulated data so that degradation characteristics of sub-pixels having the same accumulated data are the same, wherein the data accumulator is configured to accumulate the corrected modulated data (Mdata') of the corresponding sub-pixel and store the corrected modulated data (Mdata') obtained by accumulation in the memory as the accumulated data (Adata). a degradation weight reflector configured to calculate a degradation weight, based on a grayscale value of the modulated data (Mdata) of each sub-pixel, and reflect the degradation weight in corrected modulated data (Mdata') of a corresponding sub-pixel to correct the modulated data (Mdata), wherein the degradation weight reflector is configured to differently set the degradation weight according to the grayscale value of the modulated data so that degradation characteristics of sub-pixels having the same accumulated data are the same, wherein the data accumulator is configured to accumulate the corrected modulated data (Mdata') of the corresponding sub-pixel and store the corrected modulated data (Mdata') obtained by accumulation in the memory as the accumulated data (Adata).