An automatic focusing system comprises: a region configuring device which configures a main subject region including a main subject within a photographing screen; a focusing control device which controls focusing so that a focus state of the main subject is a best focus state; a focus state obtaining device which divides the photographing screen into a plurality of regions and obtains a focus state from each region; a device storing the focus state obtained from each region; a movement detecting device which references the stored focus state of each region to detect the movement of a group of regions located either within the main subject region and its vicinity or within the main subject region and are in a best focus state; and a region moving device which moves the main subject region in accordance with the movement of the group of regions that are in the best focus state.