A lipid membrane structure for delivering a substance into a nucleus of a cell, wherein lipid membrane is modified with (a) a polypeptide comprising the amino acid sequence of SEQ ID NO: 1, and/or (b) a polypeptide consisting of an amino acid sequence comprising the amino acid sequence of SEQ ID NO: 1, but including deletion and/or substitution and/or insertion of one or several amino acid residues, and having an activity of promoting migration of the lipid membrane structure into a nucleus of a cell, which can efficiently deliver a nucleic acid into a nucleus of an immunocyte such as dendritic cell.
