Image pickup mechanism, endoscope, and method of manufacturing an image pickup mechanism

An image pickup mechanism comprises: an image pickup element; a photo-detection section provided on one face of this image pickup element; a cover member that covers this one face of the image pickup element and the photo-detection section; and a lens unit that has a plurality of lenses including a plano-convex lens having a planar section and an endoscope body in which the aforementioned plurality of lenses are fixed and that is optically coupled with this image pickup section. The plano-convex lens having the planar section is arranged so that the planar section thereof faces the image pickup element at the position in the plurality of lenses nearest to the image pickup element. The planar section projects towards the image pickup element from the end of the endoscope body, and is fixed to the cover member.