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 as well as a command to not display the additional information image along with the three dimensional medical image, which is being displayed in color, the display control section displaying the additional information image in color along with the three dimensional medical image and changing a display of the displayed three dimensional medical image to a black and white display, when the command to display the additional information image is received in a state that the three dimensional medical image is being displayed in color, and ceasing display of the additional information image and returning the display of the three dimensional medical image to color display, when the command to not display the additional information is received in a state that the additional information image is being displayed in color.