An accurate wavelength meter (wavemeter) for CW lasers has been developed. The wavemeter is a Michelson-type fringe-counting two-beam interferometer, operating in vacuum. A multicoincidence fringe counting technique has also been developed by which fringe fractions are determined with an uncertainty of 1/500 of a fringe. The result of wavelength comparisons between 612- and 633-nm I2 stabilized He-Ne lasers showed good agreement with the value recommended by CIPM in 1983. The discrepancy was less than 4 x 10 to the -10th and the standard deviation of the comparison was 4 x to the -10th.