PROBLEM TO BE SOLVED: To provide a novel carrier for brain delivery of peptide medicament.SOLUTION: According to one embodiment of the invention, a carrier for brain delivery comprising the polypeptide described in either of the following (a) or (b) is provided: (a) a polypeptide comprising the amino acid sequence described in sequence number:1, (b) a polypeptide comprising the amino acid sequence obtained by addition, deletion, insertion or substitution of one or a plurality of amino acids in the amino acid sequence described in sequence number:1 and having brain transfer activity.