The application is directed to an image pickup system that includes a lens holder; an image pickup optical system that is secured by a portion of the lens holder; an image pickup device comprising a first surface and a second surface, wherein the first surface is nearer the image pickup optical system than the second surface in an optical axis direction, a light receiving sensor that receives light entering through the image pickup optical system, and a cover glass attached to the first surface of the image pickup device, wherein the cover glass comprising a fitting portion of the cover glass in an outer circumferential face of the cover glass.