A display apparatus is provided. A light beam emitted from a light source is applied through a light modulator and a projecting optical system to a scanning mirror. The light beam is reflected and scanned by the scanning mirror, and applied to a magnifying projection system entrance unit. A detection light beam emitted from a mirror angle detecting light source is reflected and scanned by the scanning mirror, and applied to a linear detector. Operation of the scanning mirror is controlled based on the position of the detection light beam which is detected by the linear detector. The present invention is applicable to a front projector or a rear projector.
