A flash controlling method is disclosed. The method includes: acquiring image data by photographing a subject; detecting a predetermined target object from the image data; calculating a distance to the predetermined target object based on a size of the detected predetermined target object; controlling an amount of flash light to be emitted based on the calculated distance; setting a predetermined threshold based on a reachable distance of the flash light; and inhibiting emission of the flash light when the calculated distance is larger than the predetermined threshold.