Provided are an endoscopic surgical device, a treatment tool, and a guide member capable of performing change to a visual field suitable for detailed observation and treatment with a simple operation, and improve surgical efficiency. An endoscope insertion part 102 of an endoscope and a treatment tool insertion part 202 of a treatment tool are insertable through an overtube 300 inserted into a body wall, and a slider is provided for moving the endoscope insertion part 102 and the treatment tool insertion part 202 forward and backward in an interlocking manner. An operating part 204 of the treatment tool inserted through the overtube 300 is provided with a guide member 230 that guides a cable part 104 so as to be movable forward and backward in an axial direction so that the cable part 104 of the endoscope 100 is kept from being separated from the surface of the operating part 300 beyond a fixed distance. Accordingly, the cable part 104 can be reliably held down by an index finger of a right hand gripping the operating part 204 of the treatment tool, and, the operation of the operating part 204 and the forward and backward movement operation of the endoscope insertion part 102 can be performed with only a right hand.
