The present invention is directed to the provision of an information input apparatus that can change the projection position of an input image by tracking a target object and can detect an information input to the input image. More specifically, the invention provides an information input apparatus includes a projection unit which projects an input image, a projection position changing unit which changes the projection position of the input image, a detection sensor which detects the position of a detection target, and an information detection unit which causes the projection position changing unit to change the projection position of the input image by tracking the position of the detection target detected by the detection sensor, and which detects an information input to the input image based on data supplied from the detection sensor.