The image display system includes a processing unit and a driving unit. The processing unit is configured to receive an image signal indicative of an instruction value of luminance of a light source. The driving unit is configured to supply a drive current to the light source in accordance with the instruction value indicated by the image signal received by the processing unit. The driving unit includes a shaping circuit and an adjusting unit. The shaping circuit includes a plurality of D/A converters and an arithmetic unit. The arithmetic unit is configured to output the drive current to the light source based on a computation result of analog signals outputted from the plurality of D/A converters. The adjusting unit is configured to determine values of digital signals inputted into the plurality of D/A converters of the shaping circuit in accordance with the instruction value.