It is intended to provide a cell having an RNA, which inhibits the function of an enzyme catalyzing the reaction of converting GDP-mannose into GDP-4-keto,6-deoxy-GDP mannose, transferred thereinto; a method of producing a glycoprotein composition by using this cell; a cell having an RNA which inhibits the function of an enzyme participating in the sugar chain modification of the binding, via a-bond, of the 1-position of fucose to the 6-position of N-acetylglucosamine at the reducing end of an N-glycoside bond type complex sugar chain, an RNA which inhibits the function of an enzyme protein participating in the intracellular synthesis of a sugar nucleotide GDP-fucose, or an RNA inhibiting the function of a protein participating in the intracellular transport of a sugar nucleotide GDP-fucose into the Golgi body, transferred thereinto; a method of producing a glycoprotein composition by using this cell; and so on.