An endoscope apparatus according to the present invention includes an insertion portion having a distal end portion and at least two channels an optical observation system provided on one surface of the distal end portion so as to face an axial direction different from a direction of an insertion axis X of the insertion portion a first channel opening provided on one surface of the distal end portion near the optical observation system an ultrasound transducer array provided on the one surface of the distal end portion and having a scanning surface Z parallel to the insertion axis and a second channel opening provided on a proximal end side of the ultrasound transducer array.
