PROBLEM TO BE SOLVED: To allow an operator to accurately select a region of interest of any shape on a medical image displayed on the display unit and set optimum window conditions for the selected region of interest.SOLUTION: One embodiment of the image display apparatus 40 comprises: a display unit 43 which displays an image with a supplied first gradation by a second gradation smaller than the first gradation and an input unit 44 which is so arranged as to be superposed on the display unit 43 and generates signals according to the position of an indication body which is in contact with an operation surface. The image display apparatus 40 also comprises a control unit 41 which detects a trajectory of the indication body on the operation surface on the basis of the signals supplied by the input unit 44, sets a region of interest on an image displayed on the display unit 44 on the basis of the trajectory, and sets window conditions on the basis of the luminance values of the pixels within the region of interest. The set window conditions are applied to the image to redisplay the image.
