1. A medical image display apparatus, comprising: a medical image obtaining section for obtaining a three dimensional medical image of a subject; a display control section for displaying the three dimensional medical image obtained by the medical image obtaining section and an additional information image that represents information added to the three dimensional medical image; and an additional information display command receiving section for receiving a command to display the additional information image along with the three dimensional medical image; the display control section displaying the additional information image along with the three dimensional medical image and changing the color of the displayed three dimensional medical image to a color which can be discriminated from the color of the additional information image, when the command to display the additional information image is received.