Disclosed is a CMOS image sensor, comprising a photodiode formed in a substrate, a floating diffusion region formed in the substrate in a manner such that it is distanced from the photodiode surrounds the photodiode and a transfer gate formed in a manner such that it is distanced from the photodiode and the floating diffusion region and formed in a boundary area between the photodiode and the floating diffusion region, thereby overlapping the photodiode and the floating diffusion region.