A structure extracting unit extracts a structure from a three-dimensional medical image, and a view point determining unit determines a view point position and a direction of line of sight of a virtual endoscopic image. An image generating unit calculates a distance between a view point position and the extracted structure, determines a display attribute of the extracted structure based on the distance and a plurality of different display attributes that correspond to different distances from the view point position and are defined for each of the structures, and generates, from the three-dimensional medical image, a virtual endoscopic image containing the structure having the determined display attribute. A display control unit displays the thus generated virtual endoscopic image on a WS display.
