A solid-state image pick-up unit comprises: a semiconductor substrate comprising an area in which a photoelectric converting portion is formed; and an electric charge transfer portion that transfers an electric charge formed by the photoelectric converting portion, wherein the electric charge transfer portion comprises: an electric charge transfer electrode including a first layer electrode and a second layer electrode; and a gate oxide film, the gate oxide film comprises a second gate oxide film formed under the second layer electrode, the second gate oxide film comprising an ONO film which comprises a SiO film, a SiN film and a SiO film in this order, and the second gate oxide film is continuously formed to cover whole of a region between the first layer electrode and the second layer electrode and a region under the second layer electrode.