IMAGE SENSING DEVICE

An image sensing device includes a first unit pixel block, a second unit pixel block, and an isolation transistor. The first unit pixel block includes a first common floating diffusion node, a plurality of first photoelectric conversion elements, a plurality of first transfer transistors configured to transmit the photocharges generated by the first photoelectric conversion elements to the first common floating diffusion node, and a first conversion gain transistor configured to change capacitance of the first common floating diffusion node. The second unit pixel block adjacent to the first unit pixel block in a first direction includes a second common floating diffusion node, a plurality of second photoelectric conversion elements, a plurality of second transfer transistors configured to transmit the photocharges generated by the second photoelectric conversion elements to the second common floating diffusion node, and a second conversion gain transistor configured to change capacitance of the second common floating diffusion node. The isolation transistor located in a boundary region between the first unit pixel block and the second unit pixel block isolates the first conversion gain transistor and the second conversion gain transistor from each other.