A medium for stem cell proliferation comprising a fibroblast growth factor, and a sulfated compound or a pharmaceutically acceptable salt thereof at a concentration promoting the growth of a stem cell in the presence of FGF, wherein the sulfated compound is at least one selected from the group consisting of (a) a sulfated polymer, excluding sulfated saccharides, wherein the sulfated polymer is at least one selected from the group consisting of sulfo group-containing polyvinyl alcohol, sulfo group-containing polyvinyl amine, sulfo group-containing polyallylamine, sulfo group-containing polyethyleneimine, sulfo group-containing α-polylysine, sulfo group-containing α-poly methyl glutamate/α-5-hydroxynorvaline (2/8) copolymer, α-polyglutamic acid-γ-taurine, sulfo group-containing triserine, sulfo group-containing serine, sulfo group-containing branched-polyglycerol and a derivative thereof, and polyethylene sulfonate; (b) a sulfated saccharide, wherein the sulfated saccharide or a pharmaceutically acceptable salt thereof is at least one selected from the group consisting of: dextran sulfate Na; cellulose SO 3 Na; xanthan gum SO 3 Na; pectin SO 3 Na; alginate SO 3 Na; maltoheptaose SO 3 Na; maltotriose SO 3 Na; maltitol SO 3 Na; sucrose 8SO 3 K; mannitol SO 3 Na; xylitol SO 3 Na; and erythritol SO 3 Na; wherein the sulfated saccharide content is not more than 250 ng/ml when the sulfated saccharide is a sulfated polysaccharide, wherein the polysaccharide is a carbohydrate wherein three or more molecules of monosaccharide are bonded by a glycosidic bond to become one molecule; (c) a sulfated substance of a saccharide polymer crosslinked by a diisocyanate compound, wherein the sulfated substance of a saccharide polymer crosslinked by a diisocyanate compound or a pharmaceutically acceptable salt thereof is maltotriose-hexamethylene diisocyanate-SO 3 Na or dextran-hexamethylene diisocyanate-SO 3 Na; (d) a sulfated substance of sugar-lactone, wherein the sulfated substance of sugar-lactone or a pharmaceutically acceptable salt thereof is gluconolactone-SO 3 Na; and (e) a sulfated substance of an organic acid, wherein the sulfated substance of an organic acid or a pharmaceutically acceptable salt thereof is tartrate-SO 3 Na. (a) a sulfated polymer, excluding sulfated saccharides, wherein the sulfated polymer is at least one selected from the group consisting of sulfo group-containing polyvinyl alcohol, sulfo group-containing polyvinyl amine, sulfo group-containing polyallylamine, sulfo group-containing polyethyleneimine, sulfo group-containing α-polylysine, sulfo group-containing α-poly methyl glutamate/α-5-hydroxynorvaline (2/8) copolymer, α-polyglutamic acid-γ-taurine, sulfo group-containing triserine, sulfo group-containing serine, sulfo group-containing branched-polyglycerol and a derivative thereof, and polyethylene sulfonate; (b) a sulfated saccharide, wherein the sulfated saccharide or a pharmaceutically acceptable salt thereof is at least one selected from the group consisting of: dextran sulfate Na; cellulose SO 3 Na; xanthan gum SO 3 Na; pectin SO 3 Na; alginate SO 3 Na; maltoheptaose SO 3 Na; maltotriose SO 3 Na; maltitol SO 3 Na; sucrose 8SO 3 K; mannitol SO 3 Na; xylitol SO 3 Na; and erythritol SO 3 Na; wherein the sulfated saccharide content is not more than 250 ng/ml when the sulfated saccharide is a sulfated polysaccharide, wherein the polysaccharide is a carbohydrate wherein three or more molecules of monosaccharide are bonded by a glycosidic bond to become one molecule; (c) a sulfated substance of a saccharide polymer crosslinked by a diisocyanate compound, wherein the sulfated substance of a saccharide polymer crosslinked by a diisocyanate compound or a pharmaceutically acceptable salt thereof is maltotriose-hexamethylene diisocyanate-SO 3 Na or dextran-hexamethylene diisocyanate-SO 3 Na; (d) a sulfated substance of sugar-lactone, wherein the sulfated substance of sugar-lactone or a pharmaceutically acceptable salt thereof is gluconolactone-SO 3 Na; and (e) a sulfated substance of an organic acid, wherein the sulfated substance of an organic acid or a pharmaceutically acceptable salt thereof is tartrate-SO 3 Na.