An image display device includes a display panel having predetermined numbers of pixels defined in horizontal and vertical directions, respectively, and an interpolated-data generation circuit whereby an expanded image data is produced in such a manner that when the number of pixels in the horizontal direction of the display panel is greater than the number of pixels in the horizontal direction of a given image signal, the interpolated-data generation circuit directly stores a plurality of image data A, B, C, D, E of the original image signal along one horizontal line at data storage locations closest to the original locations, and data at data storage locations remaining after storing all original data are given the results X, Y, and Z obtained by calculation from two original image data at locations adjacent to the respective remaining data storage locations thereby expanding the original image signal to have a resolution well matched to the resolution of the display panel without causing a reduction in contrast.