An imaging device in which an autofocus function can be performed without using brightness information is provided. In an imaging device according to one aspect, a density of points obtained by plotting two-dimensional point data of a plurality of event data as points on a plane, the event data outputted from an imaging element in a predetermined period in a state in which a focal point of a light receiving lens is adjusted by an adjustment mechanism, is calculated as a point density. When the point density is calculated, a control unit drives and controls the adjustment mechanism based on comparison results between the point density currently calculated and the point density last calculated to thereby adjust the focal point toward the in-focus position. In another aspect, an imaging device having an autofocus function can be provided without using event data.