A display control device includes: a receiver configured to receive an image signal; a measurer configured to measure the number of vertical scanning lines and horizontal scanning time of the image signal; a table generator configured to generate a provisional signal table when data measured by the measurer has not been retained in a previously prepared signal table; a detector configured to detect data for regulating an active display region of an image, from the image signal; and an updater configured to update the provisional signal table, based on a detection result by the detector.