An insertion part of an endoscope and an insertion part of a treatment tool, which are inserted in an outer tube, can be synchronously moved in the axial direction, and, even when the insertion part of the treatment tool is slightly moved in the axial direction, an excellent endoscopic image without shake is obtained. When a treatment tool of an endoscopic surgery device moves by a displacement amount over an allowance amount, an endoscope moves in interlock with the movement of the treatment tool. Moreover, the treatment tool