[Object] To always have an observation target object within the region of a picked up image in the case where an oblique-viewing endoscope is inserted into the human body for operation.[Solution] A medical supporting arm according to the present disclosure includes: a supporting arm configured to support an oblique-viewing endoscope； and a calculation unit configured to calculate a rotation angle of the oblique-viewing endoscope around an axis in a longitudinal direction, and an insertion amount of the oblique-viewing endoscope into a human body on the basis of a first expression that defines coordinates of a subject in a coordinate system in which an insertion opening allowing the oblique-viewing endo scope to be inserted into the human body serves as an origin, and a second expression that defines the coordinates of the subject positioned in an optical axis direction of an objective lens disposed at a distal end of the oblique-viewing endoscope in a coordinate system in which the distal end of the oblique-viewing endoscope serves as an origin.
