A multi-wavelength interferometer includes a beam splitter configured to split plural light fluxes into a reference beam and a measurement beam, a frequency shifter configured to shift a frequency of at least one of the reference beam and the measurement beam to make the frequencies of the reference beam and the measurement beam different from each other, an optical system configured to cause the measurement beam to be incident on a measurement surface and to cause the measurement beam reflected from the measurement surface to interfere with the reference beam to obtain interference light, a dividing unit configured to divide the interference light into a plurality of light beams, and a detection unit configured to detect the plurality of light beams divided by the dividing unit.