There is provided an endoscopic surgery device that is capable of easily acquiring an image desired by a surgeon, and that has high operability. The endoscopic surgery device includes: an outer tube body 302 that penetrates through a body wall to be inserted into a body cavity； an endoscope insertion path 304 that is provided inside the outer tube body 302； a treatment tool insertion path 306 that is provided inside the outer tube body 302； a position sensor 310 that detects a movement amount of the treatment tool insertion part 202 with respect to the outer tube body 302 when the treatment tool insertion part 202 is moved back and forth； and a control unit 314 that has a non-sensitive area where a range of an observation image acquired by an endoscope 100 is not changed if the movement amount of the treatment tool insertion part 202 is within a predetermined range when the movement amount of the treatment tool insertion part 202 is detected by the position sensor 310, and that varies a range an observation image in accordance with the movement amount of the treatment tool insertion part 202 if the movement amount of the treatment tool insertion part 202 is not within the predetermined range.
