1. An image display apparatus comprising: a plurality of light sources capable of separately controlling emission brightness for each of a plurality of divided regions in a screen; and a processor configured to: perform a determining processing that determines a target brightness of a predetermined divided region, based on image data corresponding to the predetermined divided region; perform an estimating processing that estimates the brightness of the predetermined divided region in a case where light is emitted by the light source for the predetermined divided region at an emission brightness which is based on image data in each of the plurality of divided regions; and in a case that the brightness estimated by the estimating processing is lower than the target brightness determined by the determining processing, perform a control processing that increases the emission brightnesses of two or more light sources corresponding to two or more divided regions including the predetermined divided region at the same increase rate.