The endoscope apparatus includes an endoscope insertion portion configured to be inserted into a subject and including a distal end portion, a distal end covering portion configured to cover at least an outer periphery of the distal end portion of the endoscope insertion portion and held by the distal end portion, a suction conduit provided with an opening in the distal end covering portion and configured to discharge a fluid including gas generated from an inside of the subject to outside of the subject via the opening, and a positioning portion configured to define a position of the opening of the suction conduit in a rotation direction with a long axis of the endoscope insertion portion as a center when the distal end covering portion is held by the distal end portion of the endoscope insertion portion.