A focusing controlling device is for a camera having a photographing lens and an imaging surface. The focusing controlling device includes a focus adjuster that adjusts a focus position of the photographing lens based on field curvature data. The field curvature data indicates a field curvature ratio which is a ratio of a distance between an image point of light transmitted through the photographing lens and the imaging surface to a focal distance of the photographing lens, the field curvature data being set for a partial area of the imaging surface as an average value of the field curvature ratios for the partial area.