A two-dimensional solid-state image pickup device includes a plurality of pixel regions arranged in a two-dimensional matrix in X and Y directions. Each of the pixel regions includes at least a light-receiving element, and a light-condensing element. The light-condensing element is a sub-wavelength lens including protrusions each having a size equivalent to or smaller than a wavelength of an electromagnetic wave incident on the light-receiving element. Each of the protrusions has a rounded edge.