An endoscope system, comprising: an endoscope including an imaging unit that is capable of taking an image of an imaging target, a field-of-view adjustment mechanism for varying an orientation of the imaging unit and a driver unit for driving the field-of-view adjustment mechanism; a distance measurement unit for measuring a distance from a distal end of the endoscope to the imaging target; an endoscopic position sensor for detecting a position of the endoscope in the body cavity; a position computation unit for computing positions of the distal end of the endoscope and the imaging target on the basis of information from the endoscopic position sensor and the distance measurement unit; a position storage unit for storing a position of the imaging target computed by the position computation unit; a first driving-amount computation unit for computing a driving amount for the field-of-view adjustment mechanism using the position stored in the position storage unit and the position of the distal end of the endoscope; an image storage unit for storing the image of the imaging target taken by the imaging unit; a comparison unit for comparing the image of the imaging target stored in the image storage unit with a newly taken image of the imaging target; a second driving-amount computation unit for computing a driving amount for the field-of-view adjustment mechanism depending on a result of comparison by the comparison unit; and a determination unit for determining a first driving amount computed by the first driving-amount computation unit or a second driving amount computed by the second driving-amount computation unit, which is used to drive the driver unit. an endoscope including an imaging unit that is capable of taking an image of an imaging target, a field-of-view adjustment mechanism for varying an orientation of the imaging unit and a driver unit for driving the field-of-view adjustment mechanism; a distance measurement unit for measuring a distance from a distal end of the endoscope to the imaging target; an endoscopic position sensor for detecting a position of the endoscope in the body cavity; a position computation unit for computing positions of the distal end of the endoscope and the imaging target on the basis of information from the endoscopic position sensor and the distance measurement unit; a position storage unit for storing a position of the imaging target computed by the position computation unit; a first driving-amount computation unit for computing a driving amount for the field-of-view adjustment mechanism using the position stored in the position storage unit and the position of the distal end of the endoscope; an image storage unit for storing the image of the imaging target taken by the imaging unit; a comparison unit for comparing the image of the imaging target stored in the image storage unit with a newly taken image of the imaging target; a second driving-amount computation unit for computing a driving amount for the field-of-view adjustment mechanism depending on a result of comparison by the comparison unit; and a determination unit for determining a first driving amount computed by the first driving-amount computation unit or a second driving amount computed by the second driving-amount computation unit, which is used to drive the driver unit.