An optical unit includes: a projection optical system on which light from a display unit is incident; a common optical system that projects light passing through the projection optical system to a projection target object and forms an image of a subject at a side of the projection target object; an optical member for guiding light passing through the projection optical system to the common optical system and guiding an intermediate image formed by at least a part of the common optical system to an imaging element; and an imaging optical system for forming the intermediate image on the imaging element, and an image forming position of the intermediate image is present between a component closest to a side of the projection target object among components constituting the common optical system and the optical member.