The user is allowed to more reliably recognize the approach of an endoscope or a surgical tool to a site of interest during observation of a body cavity of a subj ect using the endoscope inserted in the body cavity. A virtual endoscopic image generating unit (26) for generating, from a 3D medical image formed by a 3D medical image forming unit (5) inputted thereto, a virtual endoscopic image, in which a position of a structure of interest identified by a position of interest identifying unit (25) is the view point, a position of at least one of the endoscope and a surgical tool detected by an endoscope position detecting unit (11) or a surgical tool position detecting unit (12) is contained in the field of view of the virtual endoscopic image, and the position of at least one of the endoscope and the surgical tool is shown in an identifiable manner, is provided. A display control unit (27) causes a WS display (10) to display the generated virtual endoscopic image.
