An endoscopic observation support system comprising: 3D medical image forming means configured to form a 3D medical image representing an interior of a body cavity of a subject; position of interest identifying means (24, 30, 31) configured to identify a position of a structure of interest in the body cavity in the 3D medical image; endoscope position and posture detecting means configured to detect a real-time position and a real-time posture of an endoscope inserted in the body cavity; endoscope angle of view obtaining means configured to obtain information of an angle of view of the endoscope; virtual field of view determining means configured to determine a virtual field of view of a virtual endoscope positioned at an endoscope-corresponding position, the endoscope-corresponding position being a position in the 3D medical image corresponding to the detected position of the endoscope, based on the identified position of the structure of interest, the detected position and posture of the endoscope in the 3D medical image, and the angle of view of the endoscope, such that the position of the structure of interest is contained within the virtual field of view and the virtual field of view has continuity with an endoscope-corresponding field of view, the endoscope-corresponding field of view being a field of view of the 3D medical image corresponding to a field of view of the endoscope; virtual endoscopic image generating means configured to generate, from the 3D medical image inputted thereto, a virtual endoscopic image having the virtual field of view with a view point thereof being the endoscope-corresponding position; display control means configured to cause display means to display the virtual endoscopic image; and real endoscopic image forming means configured to form a real endoscopic image representing the interior of the body cavity by real-time imaging with the endoscope; characterised in that: the display control means is adapted to cause the virtual endoscopic image and the real endoscopic image which is formed almost at the same time when the position and posture of the endoscope used to generate the virtual endoscopic image are detected, to be displayed with being superimposed one on the other and corresponding positions between the images being aligned with each other, and the virtual field of view determining means determines the virtual field of view such that an angle of view of the virtual endoscope is wider than the angle of view of the endoscope. 3D medical image forming means configured to form a 3D medical image representing an interior of a body cavity of a subject; position of interest identifying means (24, 30, 31) configured to identify a position of a structure of interest in the body cavity in the 3D medical image; endoscope position and posture detecting means configured to detect a real-time position and a real-time posture of an endoscope inserted in the body cavity; endoscope angle of view obtaining means configured to obtain information of an angle of view of the endoscope; virtual field of view determining means configured to determine a virtual field of view of a virtual endoscope positioned at an endoscope-corresponding position, the endoscope-corresponding position being a position in the 3D medical image corresponding to the detected position of the endoscope, based on the identified position of the structure of interest, the detected position and posture of the endoscope in the 3D medical image, and the angle of view of the endoscope, such that the position of the structure of interest is contained within the virtual field of view and the virtual field of view has continuity with an endoscope-corresponding field of view, the endoscope-corresponding field of view being a field of view of the 3D medical image corresponding to a field of view of the endoscope; virtual endoscopic image generating means configured to generate, from the 3D medical image inputted thereto, a virtual endoscopic image having the virtual field of view with a view point thereof being the endoscope-corresponding position; display control means configured to cause display means to display the virtual endoscopic image; and real endoscopic image forming means configured to form a real endoscopic image representing the interior of the body cavity by real-time imaging with the endoscope; characterised in that: the display control means is adapted to cause the virtual endoscopic image and the real endoscopic image which is formed almost at the same time when the position and posture of the endoscope used to generate the virtual endoscopic image are detected, to be displayed with being superimposed one on the other and corresponding positions between the images being aligned with each other, and the virtual field of view determining means determines the virtual field of view such that an angle of view of the virtual endoscope is wider than the angle of view of the endoscope. the display control means is adapted to cause the virtual endoscopic image and the real endoscopic image which is formed almost at the same time when the position and posture of the endoscope used to generate the virtual endoscopic image are detected, to be displayed with being superimposed one on the other and corresponding positions between the images being aligned with each other, and the virtual field of view determining means determines the virtual field of view such that an angle of view of the virtual endoscope is wider than the angle of view of the endoscope.