The present disclosure relates to a signal processing device and an image display apparatus including the same. The signal processing device includes: an input interface to receive an image signal; a first image processor to generate first image frame data based on the image signal; a second image processor including a scaler to generate second image frame data scaled down in comparison with the first image frame data; and an output interface to output the first image frame data and the second image frame data, wherein the scaler generates at least one super pixel or super block and outputs the scaled down second image frame data including the super pixel or the super block. Accordingly, it is possible to generate the scaled down second image frame data with reduced error as compared to the first image frame data.