An image sensor includes a pixel array including a first shared pixel and a second shared pixel that are adjacent to each other in a row direction. The first shared pixel includes two or more photo diodes in a first row and two or more photo diodes in a second row, and the first shared pixel includes a first floating diffusion region shared by the photo diodes of the first shared pixel. The second shared pixel includes two or more photo diodes in the first row and two or more photo diodes in the second row, and the second shared pixel includes a second floating diffusion region shared by the photo diodes of the second shared pixel.