An image display device includes an approach situation information acquirer that acquires approach situation information indicating approach of at least part of a customer's body to a shelf on which a plurality of items are displayed and indicating, when there is the approach, a position of the approach on the shelf at each time; an associator that associates the approach situation information with one item of the plurality of items according to the position indicated by the approach situation information; an index value calculator that calculates an index value relating to the customer's behavior on the basis of information indicating the item associated with the approach situation information; and a display unit that displays the index value calculated by the index value calculator together with an image of the item on the basis of the association made by the associator.