Endoscope apparatus

An endoscope apparatus comprising:

• an imaging device to which a plurality of kinds of endoscopes having optical systems with different aperture diameters are connectable, the imaging device including:
• an aperture stop with a light transmission region that allows light to be transmitted to an endoscope among the plurality of kinds of endoscopes that is connected to the imaging device, wherein a size of the light transmission region is changeable;
• and
• an imaging unit that receives the light transmitted through the aperture stop and converts the light into an electric signal;
• an aperture diameter determining unit that determines an aperture diameter of the endoscope connected to the imaging device, based on an image generated by the electric signal generated by the imaging device;
• and
• a control unit that determines the size of the light transmission region formed by the aperture stop, based on the aperture diameter determined by the aperture diameter determining unit, and changes the light transmission region of the aperture stop.