An endoscope system (1) is provided with a flexible forceps insertion portion (i.e., a treatment tool insertion portion) (6) at whose distal end is provided a forceps distal end portion (i.e., a treatment tool distal end portion) (5) that receives forwards or backwards driving force and opens and closes to grip tissue, a channel (7) through which the forceps insertion portion (6) can be inserted, an insertion/extraction device (8) that inserts or extracts the forceps insertion portion (6) from within the channel (7), and an operating device (10) that supplies forwards or backwards driving force to the forceps distal end portion (5). The insertion/extraction device (8) and the operating device (10) are provided with drive shafts (13) that are driven to pivot by a motor (i.e., pivot drive source) that is fixedly supported inside an operating unit (3), rollers (15) that receive pivot driving force from the drive shafts (13) and are able to pivot so as to move the forceps insertion portion (6) forwards or backwards, and a power transmission device (16) that transmits pivot drive force from the drive shafts 13 to the rollers 15.
