An endoscope system and operation assistant device for the same is disclosed in present invention. In the state of an inserting part of the endoscope being held by a doctor, various medical apparatusused accompanying the endoscope or all functions of the endoscope can be easily manipulated. The operation assistant device for endoscope and endoscope system comprises: an endoscope having an opticalsystem for photographing, illumination etc, and an elongate inserting part with a curved part provided at front end part thereof; a manipulation indicating device which is mounted on the inserting part and freely moveable in back and forth directions along shaft of the inserting part for indicating the manipulation of the medical apparatus used accompanying the endoscope or functions of the endoscope; a control part which is provided with indicating signal from the manipulation indicating device for controlling the functions of the endoscope or the medical apparatus. Thus, various medical apparatus used accompanying the endoscope or all functions of the endoscope can be easily manipulated in the state of the inserting part of the endoscope being held by a doctor.