An OSD display control program product controlling OSD display of an image display device having a display screen, wherein the image display device includes a region ratio storage section storing, as region ratio information, the ratio of the pixel number of a region to the total pixel number of the display screen, the region in which the OSD display is performed, and the OSD display control program product makes a computer of the image display device realize: a total pixel number input step of inputting the total pixel number of the display screen as total pixel number information; a region ratio input step of inputting the region ratio information from the region ratio storage section; and a region pixel number determination step of determining, based on the total pixel number information and the region ratio information, the pixel number of the region in which the OSD display is performed.