An image display device includes: a memory unit that stores internal body image data acquired via a receiver from a capsule endoscope taking internal body image of a subject and information that is associated with the internal body image data and related to a position of the capsule endoscope within the subject; a position information acquisition unit that performs a position estimation process based on the information related to the position to acquire position information of the capsule endoscope at imaging each of the internal body images; a preferential image determination unit that determines whether each of the internal body images meets a predetermined condition; and a preferential process control unit that controls the position information acquisition unit to perform the position estimation process preferentially on the internal body image determined to meet the predetermined condition by the preferential image determination unit.