Endoscope system and medical instrument

An endoscope system comprising:

• an endoscope equipped with an elongated insertion portion which includes an image pickup/illumination optical system and a bending portion installed in a distal part;
• a medical instrument which includes a long sheath having a predetermined flexibility, extended from a distal end of the insertion portion, and including in a distal part a treating portion which opens and closes to perform various treatments in a body cavity, the long sheath including a rigid portion which is installed on a distal side of the sheath and is longer than a channel of the insertion portion and a flexible portion which is installed consecutively on a proximal side of the rigid portion and is more flexible than the rigid portion, the long sheath being inserted in the channel of the insertion portion of the endoscope;
• an operation instruction apparatus used to give commands regarding operation of the medical instrument;
• a first medical instrument drive apparatus which operates to open and close the treating portion of the medical instrument based on commands from the operation instruction apparatus;
• and
• a second medical instrument drive apparatus which moves the sheath of the medical instrument forward and backward based on commands from the operation instruction apparatus.