Appropriate stereoscopic images of an affected site are easily acquired. Provided is a stereo-endoscope device that includes an inserted portion that can be inserted into a subjects body two imaging devices that are disposed on the inserted portion with a space therebetween driving units that change the relative angle of the optical axes of the imaging devices a distance sensor for detecting the distance to the imaging devices from a treatment part of a treatment instrument that is inserted into the subjects body and is used to treat the affected site and a swivel control section that controls the driving units based on insertion information of the treatment instrument, the insertion information including the distance detected by the distance sensor.
