1. A projector comprising: an image taking part that takes an image of an area that includes a target onto which an image is being projected; a distance measuring part that calculates, from taken image data obtained by the image taking part, distance data concerning a distance between the target and the image taking part; a plane estimation part that estimates, from the distance data, a plane corresponding to the target; and a focusing adjustment part that adjusts focusing of the image being projected, based on information concerning the plane.