1. An image display device comprising: a feature value calculating section which calculates an image feature value related to the brightness of image data using parallax between image data for a right eye and image data for a left eye which form 3D image data; an expanding coefficient calculating section which calculates an expanding coefficient, which is related to brightness expanding processing performed on the image data for the right eye and the image data for the left eye, on the basis of the image feature value calculated by the feature value calculating section; a brightness expanding processing section which performs brightness expanding processing on the image data for the right eye and the image data for the left eye on the basis of the expanding coefficient calculated by the expanding coefficient calculating section; and an image display section which displays an image on the basis of the image data for the right eye and the image data for the left eye subjected to the brightness expanding processing.