An image pickup unit according to the embodiment includes an image pickup device chip having a rectangular shape in plan view, a transparent substrate which is equal in plan view dimensions to the image pickup device chip and is joined to the image pickup device chip, and a lens unit joined to the transparent substrate with the center of a light receiving portion of the image pickup chip aligned with the optical axis, in which, two locking portions are formed in the transparent substrate and two locked portions of the lens unit which is equal to or smaller than the image pickup device chip in plan view dimensions are fitted into or abut on the corresponding locking portions respectively.