A projector comprising: an image acquiring unit acquiring projection images; an identification information acquiring unit acquiring identification information of a target device among source devices that provide the projections images; a projecting unit that generates a composite image collectively including the acquired projection images, and projects the composite image on a projection plane; a position coordinates detecting unit detecting position coordinates of a pointing object that operates on the plane; a detecting unit that detects a projection region of a projection image provided by the target device, by using the acquired identification information; a converting unit that, when the position coordinates of the pointing object is in the projection region of the projection image, converts the position coordinates of the pointing object to operating information on a coordinate system of the target device; and a transmitting unit that transmits the operating information to the target device.