The present invention is directed to a camera module using a small reflective unit and an optical device for augmented reality using the same, and provides a camera module using a small reflective unit, the camera module including a lens unit configured such that one or more lenses are disposed therein and an image sensor configured to convert image light, incident through the lens unit, into an electrical signal and output the electrical signal, the camera module further including a reflective unit configured to transfer incident image light to the lens unit by reflecting the incident image light; wherein the reflective surface of the reflective unit is disposed to be inclined with respect to the optical axis of incident light in order to reflect incident image light to the lens unit, and acts as an aperture for the incident light.