A 3-branched asparagine-linked oligosaccharide derivative of the formula (1) wherein the nitrogen of amino group of asparagine is modified with a lipophilic protective group, biotin group or FITC group; a 3-branched asparagine-linked oligosaccharide derivative which contains at least one fucose in N-acetylglucosamine on the nonreducing terminal side of the asparagine-linked oligosaccharide of the derivative; asparagine-linked oligosaccharides and oligosaccharides thereof ##STR00001## wherein Q is a lipophilic protective group, biotin group or FITC group.