In a solid state image pick-up device of the type comprising a first semiconductor layer including a photoelectric conversion element array, and vertical and horizontal switching elements adapted to select the photoelectric conversion elements, a second semiconductor layer including a horizontal shift register for selecting the horizontal switching elements, a third semiconductor layer including a vertical shift register for selecting the vertical switching elements, the first, second and third semiconductor layers are insulated from each other, and gate voltage V.sub.SMOS.L impressed upon a gate electrode of a not selected horizontal switching element is made to satisfy a relation V.sub.SMOS.L .gtoreq.V.sub.WPD +F.sub.FB where V.sub.WPD represents a potential of the first semiconductor layer, and V.sub.FB a flat band voltage beneath gate electrodes of the horizontal switching elements.