An image sensing device includes: a pixel suitable for generating a pixel signal based on a first driving voltage; a ramp signal generation block based on a variable resistance, the ramp signal generation block being suitable for generating a ramp signal whose slope is controlled by a resistance value varied according to an analog gain; a noise compensation block based on a fixed resistance suitable for sensing a noise component included in the first driving voltage to generate a noise signal and reflecting the noise signal in the ramp signal; and a digital processing block suitable for generating a digital signal based on the pixel signal and the ramp signal.