An image sensor including: a substrate which has a first surface and a second surface opposite to the first surface and pixels arranged in a two-dimensional array, wherein each of the pixels includes a photodiode; a multi-wiring layer arranged on the first surface of the substrate; a color filter layer arranged on the second surface of the substrate and including color filters that respectively correspond to the pixels; and a lens layer arranged on the color filter layer and including a double-sided spherical lens, wherein the double-sided spherical lens includes at least two material layers having different refractive indexes.