An image sensor including a first pixel, a second pixel, a pixel isolation structure between the first pixel and the second pixel, a first rear anti-reflecting layer disposed on the first pixel, the second pixel, and the pixel isolation structure; a fence disposed on the first rear anti-reflecting layer, the fence being aligned with the pixel isolation structure; and a second rear anti-reflecting layer disposed on the first rear anti-reflecting layer and the fence, wherein an air gap is present between the first rear anti-reflecting layer and the fence, and wherein the air gap is surrounded by the second rear anti-reflecting layer.