A label adding unit adds labels to structures such as a body surface region, a lung region, bronchi, and pulmonary nodules of a human extracted by a structure extraction unit from a three-dimensional image of a chest. An image display control unit displays the three-dimensional image by volume rendering on a display unit. At this time, a label display determination unit determines at least one label to be displayed with the volume rendering image to be displayed based on the opacity during the volume rendering display. A label display control unit displays the determined label with the volume rendering image on the display unit.
