Endoscopic device for the intracanal surgical treatment of disc hernias, especially protrusions into the spinal canal. It consists of two tubes (1) and (2) connected together by an intermediate part (3) on which two plates (blades) (7) and (8) slide. The two plates form, at their end, a closed working space protecting the surrounding elements. One of the tubes is used as a support for the endoscope, and the second makes it possible to introduce the instruments. The plate (8) which is narrower at its lower end is used as a spacer and protector for the nerve root. The device thus allows unrestricted treatment of all types of disc hernias by operating on the spinal canal without additional risk to the nerve structures and while profiting from the relatively untraumatising nature of endoscopic surgery.