An image display apparatus comprising: a projection unit adapted to project a projection image and a GUI image, superimposed on the projection image, onto a projection surface; an object-region detection unit adapted to detect a position of a predetermined object on the projection surface; a display control unit adapted to decide a display position and a display direction of the GUI image; a system control unit adapted to control a projection operation of the GUI image performed by the projection unit based on the display position of the GUI image and the display direction of the GUI image decided by the display control unit; and a user operation detection unit adapted to detect a user operation based on the detection result by the object-region detection unit on the projection surface on which the GUI image is displayed, characterized in that the apparatus further comprises: an insertion direction determination unit adapted to determine an insertion direction of the predetermined object on the projection surface as a direction from which the predetermined object is inserted into the projection image, and wherein the display control unit is adapted to decide, in a case in which the predetermined object exists for at least a predetermined time period on the projection image, the display position of the GUI image based on the detection result by the object-region detection unit and the display direction of the GUI image based on the determination result by the insertion direction determination unit, or to decide, in a case in which the predetermined object no longer exists after existing for at least a predetermined time period on the projection image, the display position of the GUI image based on the determination result by the insertion direction determination unit and the display direction of the GUI image based on the determination result by the insertion direction determination unit. a projection unit adapted to project a projection image and a GUI image, superimposed on the projection image, onto a projection surface; an object-region detection unit adapted to detect a position of a predetermined object on the projection surface; a display control unit adapted to decide a display position and a display direction of the GUI image; a system control unit adapted to control a projection operation of the GUI image performed by the projection unit based on the display position of the GUI image and the display direction of the GUI image decided by the display control unit; and a user operation detection unit adapted to detect a user operation based on the detection result by the object-region detection unit on the projection surface on which the GUI image is displayed, characterized in that the apparatus further comprises: an insertion direction determination unit adapted to determine an insertion direction of the predetermined object on the projection surface as a direction from which the predetermined object is inserted into the projection image, and wherein the display control unit is adapted to decide, in a case in which the predetermined object exists for at least a predetermined time period on the projection image, the display position of the GUI image based on the detection result by the object-region detection unit and the display direction of the GUI image based on the determination result by the insertion direction determination unit, or to decide, in a case in which the predetermined object no longer exists after existing for at least a predetermined time period on the projection image, the display position of the GUI image based on the determination result by the insertion direction determination unit and the display direction of the GUI image based on the determination result by the insertion direction determination unit. to decide, in a case in which the predetermined object exists for at least a predetermined time period on the projection image, the display position of the GUI image based on the detection result by the object-region detection unit and the display direction of the GUI image based on the determination result by the insertion direction determination unit, or to decide, in a case in which the predetermined object no longer exists after existing for at least a predetermined time period on the projection image, the display position of the GUI image based on the determination result by the insertion direction determination unit and the display direction of the GUI image based on the determination result by the insertion direction determination unit.