IMAGE SENSING DEVICE

An image sensing device includes a first subpixel block, a second subpixel block, a first conversion gain transistor, and a second conversion gain transistor. The first subpixel block includes a first floating diffusion region and a plurality of unit pixels sharing the first floating diffusion region. The second subpixel block includes a second floating diffusion region coupled to the first floating diffusion region and a plurality of unit pixels sharing the second floating diffusion region. The first conversion gain transistor includes a first impurity region coupled to the first and second floating diffusion regions and a second impurity region coupled to a first conversion gain capacitor. The second conversion gain transistor includes a third impurity region coupled to the second impurity region of the first conversion gain transistor and a fourth impurity region coupled to a second conversion gain capacitor.