An endoscopic device inserted into a channel in an endoscope, the endoscopic device includes a curved area being protruded from an opening of a distal end of the channel an elongated flexible longitudinal shaft member having a rotation guide member located in the curved area, and a treatment unit installed at a distal end section of the longitudinal shaft member. A curve direction of the curved area and a curve direction of the rotation guide section are opposite to each other.
