An image display apparatus, comprising: a display panel; an illuminance sensor configured to sense an ambient illuminance of the display panel and to output as an illuminance sensed by the illuminance sensor; a plurality of light sources (LS1∼LS6) disposed in an edge region of a back surface of the display panel to output light; a plurality of switching elements (Sa1∼Sa6) configured to switch the light sources (LS1∼LS6); a controller configured to calculate local dimming data of each of the light sources (LS1∼LS6), wherein the controller is configured to calculate the local dimming data of the respective light source based on a corresponding region of an input image, and a processor configured to control driving times of the switching elements (Sa1∼Sa6), wherein the processor is further configured to: calculate first duties of switching control signals applied to the switching elements (Sa1∼Sa6), based on the local dimming data of the light sources (LS1∼LS6), calculate a difference in the local dimming data of the light sources (LS1∼LS6) between a respective first region of the input image and a respective second region of the input image adjacent to the first region, when the difference in local dimming data of the light sources (LS1∼LS6) between the adjacent first and second regions is above a first reference value, calculate second duties to decrease the difference in illuminance between the first region and the second region, based on the illuminance sensed by the illuminance sensor, apply switching control signals corresponding to third duties obtained by adding the first duties and the second duties to the switching elements (Sa1∼Sa6), and drive the switching elements (Sa1∼Sa6) based on the switching control signals corresponding to the third duties. a display panel; an illuminance sensor configured to sense an ambient illuminance of the display panel and to output as an illuminance sensed by the illuminance sensor; a plurality of light sources (LS1∼LS6) disposed in an edge region of a back surface of the display panel to output light; a plurality of switching elements (Sa1∼Sa6) configured to switch the light sources (LS1∼LS6); a controller configured to calculate local dimming data of each of the light sources (LS1∼LS6), wherein the controller is configured to calculate the local dimming data of the respective light source based on a corresponding region of an input image, and a processor configured to control driving times of the switching elements (Sa1∼Sa6), wherein the processor is further configured to: calculate first duties of switching control signals applied to the switching elements (Sa1∼Sa6), based on the local dimming data of the light sources (LS1∼LS6), calculate a difference in the local dimming data of the light sources (LS1∼LS6) between a respective first region of the input image and a respective second region of the input image adjacent to the first region, when the difference in local dimming data of the light sources (LS1∼LS6) between the adjacent first and second regions is above a first reference value, calculate second duties to decrease the difference in illuminance between the first region and the second region, based on the illuminance sensed by the illuminance sensor, apply switching control signals corresponding to third duties obtained by adding the first duties and the second duties to the switching elements (Sa1∼Sa6), and drive the switching elements (Sa1∼Sa6) based on the switching control signals corresponding to the third duties. calculate first duties of switching control signals applied to the switching elements (Sa1∼Sa6), based on the local dimming data of the light sources (LS1∼LS6), calculate a difference in the local dimming data of the light sources (LS1∼LS6) between a respective first region of the input image and a respective second region of the input image adjacent to the first region, when the difference in local dimming data of the light sources (LS1∼LS6) between the adjacent first and second regions is above a first reference value, calculate second duties to decrease the difference in illuminance between the first region and the second region, based on the illuminance sensed by the illuminance sensor, apply switching control signals corresponding to third duties obtained by adding the first duties and the second duties to the switching elements (Sa1∼Sa6), and drive the switching elements (Sa1∼Sa6) based on the switching control signals corresponding to the third duties.