An endoscope apparatus includes: a first endoscope that includes a first observation optical system; a second endoscope that includes a second observation optical system different from the first observation optical system, an exit pupil diameter of the second endoscope being larger than an exit pupil diameter of the first endoscope; an imaging device that is connected to one of the first and the second endoscopes, and includes an aperture diaphragm configured to pass light output from the connected one of the first and the second endoscopes, and an imaging unit configured to receive the light passed through the aperture diaphragm and convert the received light into an electric signal; and an image processing device configured to generate an image by using the electric signal generated by the imaging device. A minimum aperture diameter of the aperture diaphragm is larger than the exit pupil diameter of the first endoscope.