[Problem] To provide a glycosylated polypeptide having a uniform carbohydrate structure, wherein the glycosylated polypeptide has interferon β activity. [Solution] It was discovered that a glycosylated polypeptide having a uniform carbohydrate structure and having interferon β activity can be produced by a method that includes a step for synthesizing a glycosylated peptide fragment and at least two peptide fragments and a step for linking the glycosylated peptide fragment and the at least two peptide fragments.
