An imaging device includes a varifocal lens and an imaging sensor which outputs a signal corresponding to light. The imaging sensor includes a photoelectric conversion unit which converts light into an electric charge, electric charge reading regions, transfer control electrodes, a gate control circuit which sequentially applies control signals to the transfer control electrodes to correspond to the position of the focal point of the varifocal lens, and a reading circuit which outputs a signal corresponding to the amount of the electric charge transferred to the electric charge reading regions. The gate control circuit repeats an operation of outputting each of the control signals when the position of the focal point is located in the focal ranges during a frame period.