A solid-state imaging device includes a plurality of pixels two-dimensionally arrayed in a well region disposed on a semiconductor substrate, each pixel including a photoelectric conversion section having a charge accumulation region which accumulates signal charge; an element isolation layer which is disposed on the surface of the well region along the peripheries of the individual charge accumulation regions and which electrically isolates the individual pixels from each other; and a diffusion layer which is disposed beneath the element isolation layer and which electrically isolates the individual pixels from each other, the diffusion layer having a smaller width than that of the element isolation layer. Each charge accumulation region is disposed so as to extend below the element isolation layer and be in contact with or in close proximity to the diffusion layer.