A medical image display apparatus includes a first image output unit which outputs a real image of a subject that is grabbed by an image input unit. A three-dimensional position posture detection unit detects a position and posture of each of the image input unit and the subject and outputs position posture information. A second image output unit generates a data image of the subject based on prerecorded data of the subject using the position posture information and outputs the data image. An image display unit superposes the real image of the subject and the data image of the subject on each other and displays a superposed image. The display area of the data image of the subject output from the second image output unit is larger than that of the real image of the subject output from the first image output unit.