To overcome issues generated due to the light-shield part in a display device which displays different images towards a plurality of viewpoints, and to provide a device for easily synthesizing images to be displayed on a display part. A display controller includes: an image memory which stores viewpoint image data for a plurality of viewpoints; a writing control device which writes the viewpoint image data inputted from outside to the image memory; a parameter storage device which stores parameters showing a positional relation between a lenticular lens and the display part; and a readout control device which reads out the viewpoint image data from the image memory according to a readout order obtained by applying the parameters to a repeating regulation that is determined based on layout of the sub-pixels, number of colors, and layout of the colors, and outputs it to the display module as synthesized image data.