[Problem to be solved] To allow appropriately making a structure visible depending on a distance between a view point position of a virtual endoscope and the structure. [Solution] A structure extracting unit (24) extracts a structure from a three-dimensional medical image (M), and a view point determining unit (26) determines a view point position and a direction of line of sight of a virtual endoscopic image. An image generating unit (27) calculates a distance betwen a view point position (PI) 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 M, a virtual endoscopic image (G1) containing the structure having the determined display attribute. A display control unit (28) displays the thus generated virtual endoscopic image (GO) on a WS display (10).
