An image sensor, comprising: a photoelectric conversion element; a transfer transistor formed over the photoelectric conversion element; and a reset transistor formed over the photoelectric conversion element, formed substantially at the same level as the transfer transistor, and spaced apart from the transfer transistor by a gap, wherein the transfer transistor and the reset transistor are trench-type transistors and are symmetrical structure to each other with respect to the gap, wherein the photoelectric conversion element is a continuous layer under both the transfer transistor and the reset transistor, and is completely below the transfer transistor and the reset transistor.