Abstract: In an endoscope apparatus, an ultrasonic vibrating element is rotatably arranged at a distal end of a flexible inserting portion, this ultrasonic vibrating element is rotated by a motor provided in a subsidiary operating portion via a flexible cable extended through the inserting portion, the distal end portion of the inserting portion is bent by operating a handle provided on a primary operating portion, which is arranged at the proximal side of the subsidiary operating portion; a forceps channel is extended through the inserting portion and an opening of the forceps channel is formed in the subsidiary portion. According to such structure, the forceps can be inserted in the forceps channel easily and existing forceps having a standard length can be used as they are.