An endoscope apparatus includes an endoscope including a flexible insertion tube and a curved-shape detection sensor. The curved-shape detection sensor includes an optical fiber for propagating detection light and a sensing part provided in at least a part of the optical fiber. The curved-shape detection sensor detects a curved shape of the insertion tube based on a change of characteristics of the detection light after passing the sensing part made in accordance with a change in a curved shape of the optical fiber when the optical fiber is curved. The optical fiber is arranged on a curve axis of the insertion tube defined when the insertion tube is curved in a predetermined curve direction, or in a proximity region of the curve axis.
