An embodiment of present application provides a light beam adjusting device (100) and an optical device. The light beam adjusting device (100) includes: one or more first light incidence face (10) arranged to receive an incident light beam (20); one or more total reflection collimating face (30) arranged to totally reflect the incident light beam (20) from the first light incidence face (10) to collimate the incident light beam (20); and a first light exit face (40), from which the collimated light beam is emitted. In the above light beam adjusting device and the optical device, the incident light beam is firstly collimated into a substantially parallel light beam and then exits from the light exit face, thereby improving the luminance of the emergent light and broaden the emergent light.