Endoscope system and medical instrument

摘要

According to the present invention, there is provided an endoscope system including: an endoscope having an elongated insertion portion; a medical instrument configured to be inserted in a channel of the insertion portion of the endoscope and to have an elongated flexible sheath; and an advancing and retracting apparatus configured to advance and retract the sheath of the medical instrument in the channel with two rollers, wherein the sheath of the medical instrument is configured to have an outer diameter larger than the distance between the roller surfaces of the two rollers, and to have a frictional resistance increasing unit for increasing frictional resistance between the respective roller surfaces and the outer peripheral surface of the sheath in contact with the respective roller surfaces in a state where the sheath is inserted between the two rollers.