A laser beam intensity regulator is disclosed for independently regulating the relative intensities of the coaxial monochromatic beams eminating from a multi-wavelength laser. First, the monochromatic beams are spatially separated. Utilizing the shift of a dielectric mirror's pass band towards lower wavelengths as the angle of incident beam thereon increases, the regulator described herein includes a rotatable dielectric mirror placed in the path of the monochromatic beam to be regulated. The wavelength of the beam lies on the edge of the mirror's pass band so that the amount of light transmitted through the mirror changes as a function of the angle of incidence. The mirror is controllably rotated in response to the difference between the actual and desired beam intensities to maintain the beam at the desired intensity.