To provide an endoscopic treatment device capable of executing a series of operations from protuberance of a lesion tissue (local injection) and oblation of the protuberance part to hemostasis continuously without changing a treatment instrument to be inserted into a treatment instrument channel of an endoscope to another one with a different function.

This endoscopic treatment device comprises an endoscope, a treatment probe body 3 to be inserted into an inserting part of the endoscope, an injection needle 13 mounted on the treatment probe body 3, a fluid feed connecting means mounted on the operator's hand side of the treatment probe body 3 for feeding fluid to the injection needle, electrodes 13 for treating a lesion in the coelome with high frequency currents, a high frequency wave feed connecting means mounted on the operator's hand side of the treatment probe body for feeding high frequency currents to the electrodes, and a control device having a fluid feed means connected to the fluid feed connecting means for feeding fluid to the injection needle and a high frequency wave fee means connected to the high frequency wave feed connecting means for feeding high frequency waves to the electrodes.