A pixel driving circuit of an image sensor includes a first transistor to transmit an output signal of the photodiode to a floating diffusion node, a second transistor to reset a voltage of the floating diffusion node to a pixel voltage, a third transistor to output charges in the floating diffusion node, a fourth transistor to pre-charge an output node of the third transistor, a fifth transistor to transmit the charges in the floating diffusion node to a first node, a sixth transistor to transmit the pixel voltage to a second node, a seventh transistor to output charges in the second node, an eighth transistor to output an output signal of the seventh transistor to a column line, and a ninth transistor to output an output signal of the third transistor to the column line.