The invention includes steps of setting a main area set within the frame of a photographed image signal, and a plurality of auxiliary areas each of which is smaller than the main area, selecting one or a plurality of focus detection areas from the main area and the auxiliary areas in accordance with the in-focus position of a focus lens based on the focus signals of the main area and the auxiliary areas, and controlling the focus lens to move to the in-focus position of the focus lens in the focus detection area selected in the selecting step.