An optical unit includes a light source, a rotary reflector that rotates about an axis of rotation and includes a reflective surface that reflects light emitted by the light source, and a projection lens including an incident surface on which reflected light from the rotary reflector is incident. A shade is provided between the projection lens and the rotary reflector. The shade blocks at least a portion of light that has been incident on an emission surface of the projection lens at an angle within a predetermined range, that has been condensed by the projection lens, and that travels toward the reflective surface of the rotary reflector.