An image display device such as a medical image display device is provided for supporting that information necessary for diagnosis is sufficiently displayed and the diagnosis without any error is conducted in a short period of time. The medical image display device 1 performs a region of interest setting process for setting a region of an observation site in volume data and a lesion candidate region relating to the observation site, a display image generating process for generating a display image that allows a size of the lesion candidate region to be distinguishable, being adjacent to the observation site on a projection line of interest, when a pixel having a reference pixel value on the projection line of interest corresponds to a pixel of the region of the observation site, and an image displaying process for displaying the display image being generated.
