An endoscope system (11) is provided with: an endoscope (12) comprising an insertion section (17) provided with a channel that is inserted into a body cavity and that has a treatment tool inserted into the interior thereof, an operating section (16) that is connected to the insertion section (17) for the purpose of operating the insertion section (17), and an operating lever (63) that is provided to the operating section (16) and that transmits operating force to the treatment tool (13) by holding and moving the treatment tool (13) and an assist tool (14) that assists the movement of the treatment tool, said assist tool (14) comprising a flexible tube (55) in which an insertion path (58) is formed for inserting the treatment tool (13) that is inserted in the channel of the insertion section (17), a connecting section (45) that is connected to one end of the flexible tube (55) and that is formed so that the channel and the insertion path (58) are connected, and a holding section (56) that is mounted to the vicinity of the other end of the flexible tube (55) and that holds the operating section (16) so that the other end of the flexible tube (55) is oriented toward the side on which the operating lever (63) is arranged.Linvention concerne un système dendoscope (11) qui comprend : un endoscope (12) comprenant une section dinsertion (17) ayant un canal qui est inséré dans une cavité corporelle et qui a un outil de traitement inséré en son sein, une section dactionnement (16) qui est reliée à la section dinsertion (17) dans le but dactionner la section dinsertion (17), et un levier dactionnement (63) qui est situé sur la section dactionnement (16) et qui transmet une force dactionnement à loutil de traitement (13) par retenue et déplacement de loutil de traitement (13) et un outil dassistance (14) qui assiste le mouvement de loutil de traitement, ledit outil dassistance (14) comprenant un tube flexible (55) dans lequel un trajet dinsertion (58) est formé pour insérer lou
