  We propose a new method to estimate cosmological parameters using the baryon
fraction of clusters of galaxies for a range of redshifts. The basic assumption
is that the baryon fraction of clusters is constant, which is a reasonable
assumption when it is averaged within a Mpc scale. We find that the baryon
fraction vs. redshift diagram can estimate the cosmological parameters, since
the derived value of the baryon fraction from observations depends on the
adopted value of cosmological parameters. We also discuss some points in
comparing theoretical calculations with observations.
