Vole lllvesnguted the surface roughness charactenstics of the super~polished mirror substrate made by bowl-feed technique. in comparison with the case of fresh-feed technique. Fresh-feed techmque and bowl-feed technique were tried lor substrate surface polishing, and the surface roughne~s was estimated by phase-measunng interferometry. l11e slilface roughness of the substrate after bowl-feed procedure was Improved approxImately three times as fine as that after fresh-feed procedure. and tbe nns roughness of less than $0.5AA$ and up to $0.3AA$ at its best was obtained for the bowl-feed procedure. The surface roughness changes by (he bowl-feed technique. compated with tbe fresh-feeclleclmique. were analyzed witb tbe help of both 1 -dimensional roughne,>s profde and rougbness amplItude spect1U1l1 of the polished substrate, whIch ascertained that the final polishing partIcle size of the bowl-feed ptocedure was much smaller than that of the fresh~feed procedure. edure.